EXTRACELLULAR MICROBIAL LIPOHETEROPOLYSACCHARIDES AND DERIVATIVES, THEIR PREPARATION AND COMPOSITIONS CONTAINING THEM, AND THEIR USES

Abstract: Growth of Acinetobacter Sp. ATCC 31012 on various sub­ strates and under varying conditions has been used to pro­ duce two classes of extracellular microbial protein-associated lipopolysaccharides (the "emulsans") which, on a weight-­ for-weight basis, are probably the most efficient emulsifiers discovered and which possess certain characteristics that permit these unique extracellular microbial lipopolysac­ charides to be widely used in cleaning oil-contaminated ves­ sels, oil spill management, and enhanced oil recovery by chemical flooding. These classes have been named α-emulsans and β-emulsans, both of which have substan­ tially the same polymer backbone but differ from each other in certain important structural aspects. Deproteinization of emulsans by hot phenol extraction produces the lipopolysac­ charide components (the "apoemulsans") of each of such th emulsans, which components have been shown to be com­ pletely N-acylated and partially O-acylated heteropolysac­ charides made up of a major amounts of D-galactosamine and an aminouronic acid, the O-lipoacyl portions of such apoemulsans containing varying percentages of fatty acid esters in which the fatty acids contain from about 10 to about 18 carbon atoms. Base hydrolysis under mild conditions of the emulsans and apoemulsans produces derivatives (the "ψ-emulsans" and apo-ψ-emulsans", respectively) which are completely N-acylated and partially to completely O-deacylated. Base hydrolysis under strong conditions of any of these products produces another derivate (the "proemul­ sans") which is completely O-deacylated and is partially H-deacylated. Emulsans and apoemulsans, both of which biopolymers are strongly anionic, exhibit a high degree of specificity in the emulsification of hydrocarbon substrates which contain both aliphatic and cyclic components. In addi­ tion, these extracellular microbial polysaccharides as well as their O-deacylated and N-deacylated derivatives are adsorbed on and capable of flocculating aluminosilicate ion-­ exchangers, such as kaolin and bentonite.

Description: EMULSANS ABLE OF CONTENTS Paqe 1. Introduction 5 2. Background of the invention ............ 6 3. Summary of the Invention 8 4. Nomenclature........................... 17 5. Brief Description of the Drawings ..... 19 6. Production of a-Emulsans and Apo--a-emuisans 22 6.1. Acinetobacter Sp. ATCC 31012 ...... 23 6.2. Fermentation Media ................ 24 6.2.1. Utilizable Carbon Sources 24 6.2.2. Additional Nutrients 26 6.2.3. Divalent Cations .................... 27 6.3. Fermentation Process Conditions ....... 27 6.3.1. Aeration ............................ 28 6.3.2. Agitation ........................... 28 6.3.3. Temperature and pH .................. 29 6.3.4. Defoaming ........................... 29 6.4. Extracellular Production of Emulsans ...30 6.4.1. Standard Assay for Emulsifyimng Activity ........................ 30 6.4.2. Extracellular Production cf a-Emulsans 32 6.4.3. Extracellular Production of ss-Emulsans ...................... 33 6.4.4. Distribution of Emulsifying Activity in Fractions of Growth Culture ....... 34 6.5. Deproteinization ................ 35 6.6. Isolation and Purification ...... 36 6.6.1. Heptane Pertitioning .......... 37 Paa e 6.6.2. Ammonium Sulfate Precipitation 37 6.6.3. Quaternary Ammonium Salt Precipitation 38 7. Chemical and Physical Properties of Emulsans and Apoemulsans..................................... 38 7.1 Preparation of Samples for Analytical Characterization 39 7.1.1. Preparation of Emulsan Samples 39 7.1.2. Preparation of Apoemulsan Samples 39 7.1.3. Ammonium Sulfate Fractionation of Apo-&alpha;-Emulsan................................. 40 7.1.4. Quaternary Ammonium Salt Precipitation of Apo- a-Emulsan 41 7.2. Chemical Characterization 42 7.2.1. Chemical Composition of Emulsans and Apoemulsans..................................... 42 7.2.2. Alkaline Hydrolysis of Apoemulsans.... 43 7.2.3. Acid Hydrolysis of Apoemulsan................ 7.24. Identification of Sugar Components.... 45 7.2.5. Identification of Fatty Acids 47 7.3. Physical Characterization 50 7.3.1. Intrisic and Reduced Viscozity.............. 50 7.3.2. Sedimentation Velocity Analysis 51 7.3.3. Estimation of Molecular Weight........ 51 7.3.4. Spectral Properties ............. 51 7.4. Conclusions on Structure 52 7.5. Variations in Structure 54 7.6. Immunological Characterization............... 57 8. Emulsifying Properties 58 8.1. Kinetics of Ernulsan-Induced Emulsion Formation 58 8.2. Effect of F and Salt Concentration on Emulsion Formation.......................... Paae 8.3. Stability of Emulsan-Induced Emulsions 60 8.4. Lowering of Oil/Water Interfacial Tensions 62 9. Specificity of the Hydrocarbon Substrate 62 9.1. Emulsification of Petroleum Fractions 63 9.2. Emulsification of Pure Hydrocarbons............ 63 and ss-Emulsans...................................... 70 9.3. Emulsification of Mixtures of Pure Hydro carbons 65 9.4. Effect of Addition of Aliphatic and Aromatic Compounds on Emulsification of Petroleum Fractions 70 10. Summary of Differences Between a-Emulsans 11.1. Non-Adsorption on Sand and Limestone.......... 75 10.1. Differences in Yield ^ 72 10.2. Differences in Structure 73 10.3. Differences in Emulsifying Activity 75 11. Sorptive Properties of Emulsans and their Derivatives on Solid Substrates 75 11.2. Adsorption on Aluminosilicate Clays 76 11.3. Flocculation of Clays......................... 77 11.41 Relationship of Flocculation to Breakinc Oil/Water Emulsions................................. 78 12. Environmental and Energy-Relate Uses 79 12.1. Cleaning Oil-Contaminated Vessels 79 12.1.1. Scope of the Problem. 79 12.1.2. Oil Tankers and Pollution 80 12.1.3. Economic Considerations..................... 82 12.1.4. Utilization of &alpha;-Emulsan in Clean- ing Oil-Contaminated Vessels....... 12.2. Oil Spill Management........................ 85 12.3. Enhanced Oil Recovery......................... 86 13. Examples........................................ 87 13.1. Preparation of aEmulsan from Ethanol in Fresh Water Media................................ 87 Pac 13.2. Preparation of a-Emulsan from Ethanol in Sea Water Media ........................ 89 13.3. Preparation of c-Emulsan from Fatty Acid Salts .......................... 89 13.4. Preparation of -Emulsan from Sodium Palmitate ................................. 91 13.5. Preparation of ss-Emulsan from hexadecane 91 13.6. Preparation of Apo-&alpha;-Emulsan ........... 92 13.7. Preparation of Apo-ss-Emulsan................ 95 13.8. Preparation of #-Emulsans ................ 95 13.9. Preparation of Proemulsan 95 13.10. Purification of a-Emulsan by Precipitation with Ammonium Sulfate ........................ 96 13.11. Purification of &alpha;-Emulsan by Precipitation wit Quaternary Ammonium Salts 97 13.12. Purification of B-Emulsan by Heptane Partitioning .................................... 98 13.13. Ammonium Sulfate Fractionation of Apo-&alpha;-Emulsan ............................. 99 13.14. Emulsification of Petroleum Fractions by &alpha;-Emulsans and ss-Emulsans ................ 102 13.15. Emulsification of Mixtures of Petroleum, Fractions and Pure Hydrocarbons by &alpha;-Emulsan ................................ 104 13.16. Cleaning Oil-Contaminated Vessels ....... 106 13.17. Effect of Mobility Control Polysaccharides on Emulsion Formation with Emulsans ......... 108 13.18. Absorption of Emulsans on Clays , 110 13.19. Flocculation of Clays By Emulsans .............. 112 13.20. Flocculation of Clays by Proemulsan 11 13.21. Breaking Emulsan-Induced Emulsions 113 13.22. Removal of Oil from Sand by Emulsan.,..,.... 114 13.23. Removal of Oil fro Limestone by Emulsan.... 117 1. INTRODUCTION This invention relates to extracellular microbial polysaccharides (herein generically called "emulsans") produced by Acinetobacter Sp. ATCC 31012 and, more particularly, to a new class of extracel ] ular microbial proteinassociated lipopolysaccharides (herein collectively called "a-emulsans") produced by this organism and its mutants or recombinants, and provides process for the production of the a-emulsans. The invention further relates to the deproteinized lipopolysaccharides (herein collectively called "apoemulsans) obtained from such emulsans, as well as to the divalent metal, ammonium and quaternary ammonium salts of such emulsans and apoemulsans. These extracellular microbial polysaccharides, which include both the emulsans and apoemulsans and their respective salts, are among the most efficient oil-in-water emulsifiers ever discovered and possess high degree of specificity in both frcs ater and sea water for emulsifying those hydrocarbon substrates which contain both aliphatic and aromatic orotber c,'clic components1 properties which make these unique bioemulsifiers ideal for use in cleaning oil-contarninated vessels, oil spill management, and enhanced oil recovery by chemical flooding. The i:ivention further relates to cleaning oilcontaminated vessels, such as tankers, barges, storage tanks, tank cars and trucks, pipelines and other oilcontaminated containers used to transport or store crude oil or petroleum fractions, in such manner that the residual oil or hydrocarbonaceous residues may be recovered forfue: value or for refining. The invention provides an improved process for cleaning the hydrocarbonaceous residues, including residual petroleum or crude oil, from such oil-contaminated vessels using the new class of extracellular microbial lipopolysaccharides (the "&alpha;-emulsans") produced by Acinetobacter Sp. ATCC 31012 or its mutants or recombinants to form an aqueous oil-inwater emulsion of such hydrocarbonaceous residues from which the oil may be recovered. On a weight-for-weight basis, the a-emulsans are probably the most efficient emulsifiers discovered and possess a high degree of specificity in the emulsification of the types of hydrocarbonaceous residues found in such oil-contaminated vessels. 2. BACKGROUND OF THE INVENTION A wide variety of petroleum-degrading microorganists has been found to brinq about the formation of oil-in-water emulsions while growing on hydrocarbons. These emulsions are microbioloaical in origin and appear to be mediated either by the cells themselves or by the production of extracellular emulsifying agents. For example, the growth of Mycobacterium rhodochrous NCIB 9905 on n-decane yields en emulsifying factor which was reported by R. S. Holdom et al. [O. Apple Bateriol., 32, 448 (1969)] to be a nonionic detergent. J. Ignchi et al. [Agric Biol. Chem., 33, 1657 (1969) found that Candida petrophilium produced an emulsifying agent composed of peptides and fatty acid moieties, while T. Suzuki et al. [Agric. Biol. Chem 33, 1619 (1969)] found trehalose lipid in the oil phase of culture broths of various strains of Arthrobacter, Brevibacterium, Corynebacteriun: and Norcardia. Torulopsis qropengiesseri was found to produce a sophorose lipid, while rhamnolipids are reported by h. Hisatsuka et al. lAgric. Biol. Chem., 35, 686 (1971) to have been produced by Pseudomonas aeruqinosa strain S7B1 and by S. Itoh et al. [Agric. Biol. Chem., 36, 2233 (1971)) to have been produced by another P. aeruginosa strain, KY4025. The growth of Corynebacterium hydrocarbolastus on kerosene was reported by J. E. Zajic and his associates [ Dev. Ind. Microbial. 12, 87 (1971); Biotechrjol. Bioeng., 14, 331 (1972); Chemosphere, 1, 51 (1972); Crit. Rev. Microbiol., 5, 39 (1976); United States patent No. 3,997,398] to produce an extracellular neteropolysaccharide which, among other properties, emulsified kerosene, Bunker C fuel oil and other fuel oils. In United States patent No. 3,941,692, we described the use of an Arthrobacter species, RAG-1 (which, upon deposit with the American Type Culture Collection, was designated as Arthrobacter Sp. ATCC 31012 and is now known to have been an Acinetobacter species and has been redesignated as Acinetobacter Sp. ATCC 31012) to clean oil-contaminated tank compartments by allowing the organism to aerobically grow on the oily wastes in such tanks using sea water containing added nutrients. Curiric; that microbially-induced cleaning process the organism appeared to secrete one or more dispersants during the fermentation, since the cell-free fcrmentation medium was also effective in cleaning waste oil from such tanks. Further studies on the microbial degradation of crude oil by this organism [ Appl Microbiol., 24, 363 (1972); Appl. Microbiol., 30, 10 (1 75), howled that RAG-1 emulsified the oil during exponential growth, probably by producing an extracellular emulsifying agent which acted to break up thew oil droplet into smaller units and thereby produce new surface area, necessary for the increasing cell population. At the 1st Internationel Congress for Bacteriology Iiuld September 2-7, 1973 tInt. Assoc. Microbiolw Soc. Abstracts, Vol. II, p. 201], we reported that this extraccllular emulsifying agent had been partially purified from stationary phase cultures of RAG-1 growinq on 0.48 hexadecane, 0.07 M urea and 5.8 mM dibasic potassium phosphate in sea water. The partially purified extracellular emulsifying agent was obtained by extensively dialysing and then lyophilizing the cell-free fermentation broth, yielding 0.25 mg per ml of culture fluid of a dry powder which was capable of forming a stable oil-in-water emulsion with. 40 times its weight of crude oil. Notwithstanding the many publications on the subject, however, microbially-induced emulsification of oil is poorly understood from both mechanistic and teleological points of view. Microorganisms can utilize crude oil as a substrate for growth with or without concomitant oil emulsification. Where emulsification has occur because of the production of extracellular emulsifying agents, in general the preparations have not been purified sufficiently to identify the active components. In sum, none of tiles extraceilular Dioemuisifiers has been well characterzeo and very little is known about their chemical proe±ties, mode of action or biological function. 3. SUMMARY OF THE INVENTION The present invention is based upon part of multitude of discoveries made in connection with further work done on the bioemulsifiers produced by Acinetobacter pp. ATCC 31012, among the most important of which discoveries were: Firstly, that the Acinetobacter bioemulsifier previously produced by growing Acinetobacter Sp. ATCC 31012 (also known as strain RAG-1) on crude oil or hexadecane is an extracellular microbial protein associated lipopolysaccharide (which we have herein called Uemulsanll and given the common name 'proto emulsans"), in which the lipopolysaccharide is an N- and 0-lipoacylate heteropolysaccharide made up of major amounts of D-galactosamine and an aminouronic acid, the 0- lipoacyl portion of the lipoheteropolysaccharide containing from 2 to 3 percent by weight of various fatty acid esters in which (a) the fatty acids contain from about 10 to about 18 carbon atoms; and (b) less than 50 percent by weight of such fatty acids are composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid; Secondly, that growth of Acinetobacter Sp. ATCC 31012 on ethanol as the primary assimilable carbon source yields a significantly different extracellular microbial protein-associated lipopolysaccharide (which we have herein called "&alpha;-emulsans"), in which the lipopolysaceharide is also an N- and C- lipoacylated heteropolysaccharide made up of major amounts of D-qalactosamine and an aminouronic side but in which tiC J-l pocyl portion of the lipohetero- polysaccharide contains at least 5 percent by weight (and, more often, between 7 o 14 percent by weight and occasionally as high as 19 percent by weight) of various fatty acid esters in whicjj (a) the fatty acids contain from about 10 to about 18 carbon atoms which are usually distributed in different ratios than those in the low-ester protoemulsans; and (b) rnore than 50 percent by weight or more of such fatty acids are composed of 2-hydroxydodecanoic acid and 3-hyroxyo- decanoic acid; Thirdly, that &alpha;-emulsans rather than -emulsas may also be produced by growing Acinetobacter Sp. ATCC 31012 on fermentation media containing one or more fatty acid salts as the primary assimilable carbon source; Fourthly, that a-emulsans are much more effective than 5-emulsans in the emulsification of various crude oils and gas-oils and, in some instances (such as the emulsification of Bunker C fuel oil), efficient form stable emulsions where ss-emulsans have no effect; Fifthly, that both a-emulsans and ss-emulsans exhibit specificity in the emulsification of various types of hydrocarbons; Sixthly, that upon deproteinization of the emulsans all of the emulsifying activity is in the respect N- an6 0-lipoacyl heteropolysaccharides (which we have herein generically called "apoemulsans" specifically called "apo-a-emulsan" or "apo-ss-emulsan" depend ing upon the particular emulsan from which such deproteinized derivative was formed); ; Seventhly, that base hydrolyses of a-emulsan and ss-emulsan under mild conditions yield a common deriva tive (which we have herein called "#-emulsans" and given the common name "pseudoemulsans") which retains about 50 percent of the emulsifying activity of the a-emulsans, the structure of which w'-emulsans is the N-acylated Poly[D-galactosamine/aminouronic acid] in which (a) the amount of fatty acid esters is between 0 and 1 percent by weight of the polysaccharide; and (b) part of the N-acyl groups are 3-hydroxydodecanoyl groups; Eighthly, that base hydrolyses of a-emulsan and 3-enulsan under strong conditions yield a derivative (which we have herein called "proemulsans") which has no emulsifying activity and which is structurally a partially N-acylated poly[D-galactosamine/aminouronic acid); Ninthly, that antibodies prepared against -ci- san cross-react in an identical fashion with &alpha;-emulsa: : apo- a -emulsan1 apo- e -emulsan, -emulsan and proemul- san, indicating that the emulsans and their deproteinized and partially deacylated derivatives have approxi mately the same polymer backbones, which are poly[D galactosamine/aminouronic acid] polymers; Tenthly, that the emulsans and their respectuive deproteirized derivatives are not affected hy high concentrations of sodium chloride but require small amounts (from 1 to 100 mM and preferably from 5 to 40 mM) of at least one divalent cation, such as magnesium, calcium or manganese, to function effectively as emulsifyinc agents for hydrocarbon substrates, which divalent cations are present in sea water, connate water and most "hard" water but must be added to "soft" water; ; Eleventhly, that the emulsans on a weiqnt-for weight basis are very efficient oil-in-water emul sifiers and, moreover, possess certain characteristics that permit these uniqe extracellular microbial polysaccharides to be widely used In cleaning oil contaminated vessels, oil spill management, and enhanced oil recovery by chemical flooding; and Finally, that the emulsans and their depro- teinized and deacyclated derivatives are strongly adsorbed onto aluminosilicate ion-exchanges and are unusually efficient bioflocculents which may be use to mediate flocculation of various types of alurino silicate clays, such as kaolin and bentonite. Based on some of these discoveries, the invent 10! provides several new classes of extracellular microbial lipopolysaccharides and their derivatives selected from. the group consisting of (a) the extracellular microbial protein associated lipopolysaccarides (herein collectively called "&alpha;-emulsans") producible by Acinetobacter Sp. ATCC 31012 and its mutants, in which the lipopolysaccharide components (herein collectively called "apo-a-emulsan are completely N-acylated and partially 0-acylated heteropolysaccharides made up of major amounts of D-galactosamine and an aminouronic acid, such apo-aemulsans containing at least 5 percent by weight of fatty acid esters in which (1) the fatty acids contain from about 10 to about 18 carbon atoms; and (2) about 50 percent by weight or more of such fatty acids are composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid; (b) the deproteinized extracellular microbial lipopolysaccharides (herein collectively called "apo-a-emulsans") obtainable from the a-emulsans proiucible by Acinetobacter Sp. ATCC 31012- and its mutants, the apo-aemulsans being completely N-acylate and partially 0-acylated heteropolysaccharides made up of major amounts of D-galactosamine and an aminouronic acid, the apo-a-emulsans containing at least 5 percent by weight of fatty acid esters in which (1) the fatty acids contain from about 10 to about 18 carbon atoms; and (2) about 50 percent by weight or more of such fatty acids are composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid; (c) the deproteinized extracellular microbial polysaccharides (herein collectively called 'sapo-ffi- emulsans")obtainable from the $-emulsans producible by Acinetoacter µg, ATCC 31012 and its mutants, the apoemulsans being completely N-acylated and partially 0-acylated heteropolysaccharides made up of major amounts of D-galactosamine and an aminouronic acid, the apc-5-emulsans containing less than 5 percent by weight of fatty acid esters in which (i) the fatty acids contain from about 10 to about 18 carbon atoms; and (2) less than 50 percent by weight of such fatty acids are composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid; (d) the 0-deacylated extracellular proteinassociated microbial polysaccharides (herein collectively called the "+-emulsans")obbainable from the emulsans producible by Acinetobacter Sp. ATCC 31012 and its mutants, the protein-free components of such -emulsans being completely N-acylated heteropolysaccharides made up of major amounts of D-galactosamine and an aminouronic acid and containing from 0 to 1 percent by weight of fatty acid esters in which, when present, the fatty acids contain from about 10 to about 18 carbon atoms; ; (e) the deproteinized 0-deacylated extracellular microbial polysaccharides (herein collectively called the "apo-s-emulsans") derivable from either a-emulsans, ss-emulsans, t-emulsans, apo-W-emulsans or apo- S- emulsans, the apo- -emulsans being completely Nacylated heteropolysaccharides made up of major amounts of D-galactosamine and an aminouronic acid and containing from 0.to 1 percent by eight of fatty acid esters in which, when present, the fatty acids contain from about 10 to about 18 carbon atoms; ; (f) the deproteinized 0-deacylated extracellular microbial polysaccharides (herein collectively called the "proemulsans")derivable from either a -emulsans, B -emulsans, 9 -emulsans, apo-a-emulsans, apo-ss-emulsans or apo-*-emulsans, the proemulsans being poly [ D-galactosamine/amino uronic acid] biopolymers in which (1) none of the hydroxy group are acylated; and (2) from none to all, e.g. one to all, of the amino groups are acylated, and (g) the salts, especially the divalent metal, ammonium and quaternary ammonium salts, of such &alpha;-emulsans, apo-&alpha; ;-emulsans, apo--emulsans, -emulsans, apo,-emulsans and proemulsans It will be appreciated that the extracellular microbial protein-associated product termed herein "a-emulsan" produced by Acinetobacter Sp. ATCC 31012 or a mutant thereof is usually a mixture of such proteinassociated lipopolysaccharides, Similarly, the 0-emulsan produced by Acinetobacter 22. ATCC 31012 or a mutant thereof' is usually a mixture, and the above specified derivatives of a-emulsan and ss-emulsan obtained therefrom are correspondingly mixtures. The a-emulsan, -emulsan, apo-a-emulsan, apo-ss- emulsan,y-emulsan, apo-p-emulsan and proemulsan have approximately the same polymer backbones, being poly[Dgalactosamine/aminouronic acid] polymers. They are made up of major amounts of D-galactosamine and an aminouronic acid, i.e. the D-galactosamine and aminouronic acid units together total at least 50 % of the polymer backbone and may constitute 100 % of the backbone. The fatty acid component is usually a mixture of fatty acids. Substantially all of the fatty acids in such mixture have from 10 to 18 carbon atoms, that is, most or all have a number of carbon atoms in the range of from 10 to 18. The invention further provides emulsifying agents comprising an aqueous solution in e.g. waukro Besh water containing at least 10 mcg/ml, e.g. up to 20 mg/ml,of such a-emulsans, and from about 1 to about 100 mM of at least one divalent cation. Using the data contained herein, the emulsifying agents of the invention may be used, among other things, (t) for cleaning hydrocarbonaceous residues, including residual petroleum, from tankers, barges, storage tanks, tank cars and trucks, pipelines and other containers; (2) for cleaning oil spills which are floating on the sea or which have been washed ashore or which are deposited on land; and (3) for the enhanced recovery of oil b. chemical flooding techniques, particularly with respect to those petroleum reservoirs located in sand or sandstone or limestone formations. The invention also contemplates those polyanionic heteropolysaccharides biopolymers which are produced microbiologically (regardless of the orqanisr used) or by semi-synthetic techniques (such as by enzy- matic activity) and in which (a) substantially all of the sugar moieties are N-acylated amino sugars, a portion of which is N-acylated D-galactosamine and anothe- portion of which is an aminouronic acid (such as D-galactosamine- uronic acid, D-glucoseamineuronic acid), a part of the N-acyl groups of such heteropolysaccharide being N-(3 hydroxydoccanoid) groups; and (b) at least 0.2, and preferably from about 0.5 to about 0.75,micromoles per milligram of such heteropolysaccharide consists of fatty acid esters in which (1) the fatty acids contain from about 10 to about 18 carbon atoms, and (2) about 50 percent or more by weight of such fatty acids are composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid. Based on some of these discoveries, the invention also provides a process for producing extracellular microbial lipopolysaccharides which comprises (A) inoculating an aqueous fermentation medium containing a growth-sustaining amount of a medium which promotes the production of a-emulsan by Acinetobacter Sp. ATCC 31012 or a mutant thereof, e.g. ethanol or one or more fatty acid salts, with a culture of Acinetobacter Sp. ATCC 31012 or its tants; and (B) aerobically growing the microorganism in such fermentation medium, while adding additional amounts of said medium, e.g. ethanol or fatty acid salt or salts, to sustain growth, for a period of time sufficient to produce extracellular microbial protein-associated lipopolysaccharides (herein col Iztively called "a-emulsans") in which the lipopolysac chloride components (herein collectively called "apo-- emulsans") of such a-emulsans are completely N-acyled and partially 0-acylated heteropolysaccharides made up of major amounts of D-galactosamine and an aminouronic acid, such apo-a-emulsans containing at least 5 percent or above by weight of O-substituted fatty acid esters in which (1) the fatty acids contain from about 10 to about 18 carbon atoms and (2) about 50 percent by weight or more of such fatty acids are composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid. The invention further provides those cellfree emulsifying agents comprising an aqueous solution in sea water or fresh water containing from about 10 mcg/ml to about 20 mg/ml of such a-emulsans, and from about 1 to about 100 mM of at least one divalent cation. Using the data contained herein, these emulsifying agents produced by the process of the invention may be used, among other things, (1 for cleaning hydrocarbonaceous esidues, including residual petroleum, from tankers, barges, storage tanks, tank cars and trucks, pipelines and other containers; (2) for cleaning oil spills which are floating on the sea or which have been washed ashore or which are deposited on land; and t3) for the enhanced recovery of oil by chemical flooding techniques, particularly with respect to those petroleum reservoirs located in sand or sandstone or limestone formations. The invention also provides an improved process for cleaning hydrocarbonaceous residues, including residual petroleum, from oil-contaminated tankers, barges, storage tanks, tank cars and trucks, pipelines and other containers used to transport or store crude oil or various petroleum fractions, which comprises ( ) washing the oil-contaminated surfaces of such vessels with ar. lsifying agent comprising an aqueous solution e.g. in sea water or fresh water containing (1) at least 1U mcg/ml, eg. up to 20 ma/mL, of the extracellular microbial protein-associated lipopolysaccharides (herein collectively called 'la-emulsansll) produced by Acinetobacter Sp. CC 31012 and its mutants, in which the lipopolysaccharide components (herein collectively called "apo-a-emulsans") are N- and l-lipoacylated heteropolysaccharides made up of major amounts of D-galactosamine and an afliinouronic acid, such apo-a-emulsans containing at least 5 percent by weight of fatty acid esters in which (i) te fatty acids contain from about 10 to about 18 carbon atoms; and (ii) more than 50 percent by weight of such fatty acics are composed of 2'-hydro;'ydodecanoic acid and 3-hydroxydodecanoic acid; and (2) from about 5 mM or higher of at least one divalent cation, thereby forming an oil-inwater emulsion of such hydrocarbonaceous residues; and (b) removing such oil-in-water emulsion from the washed vessel. This aspect of the invention also contemplates using this improved cleaning process in conjunction with: various recovery systems, such as oil-water separators, so that the hydrocarbonaceous residues may be recovercc from such oil-in-water emulsion. 4. NOMENCLATURE A new lexicon has been used herein to identify and refer to the various types of extracellular microbial polysaccharides and their semi-synthetic derivatives which are derived from Acinetobacter A5 ATCC 31012 and its mutants. These new words are "emulsans", " temulsans", $-emulsans"1, "#-emulsans", "apoemulsans", "apo-&alpha;-emulsans", "apo-ssemulsans", "apo-Q-emulsans" and "proemulsanas", which are defined as follows: The name "emulsans", which reflects the polysaccharide structure of these compounds and the exceptional emulsifying activity of the biologically produced materials, has been created to identify generically those extracellular microbial protein-associated lipoheteropolysaccharides produced by Acinetobacter A5 ATCC 31012 and its mutants, which may be subdivided into the a-emulsans and the 6-emulsans. The name "apoemulsans", the prefix of which is derived from the Greek word atiu rteaning frcrn", has been created to identify generically those deproteinized lipopolysaccharides obtained from the emulsans. The name "a-emulsans11 defines those extracellular microbial protein-associated lipopolysaccharides produced by Acinetobacter g. ATCC 31012 and its mutants in which the Iipopolysaccnaride components, (i.e., without the associates protein) are completely N-acylated and partially O acylated heteropolysaccharides made up of major amounts of D-galacto samine and an aminouronic acid, the lipopolysaccharide components containing at least 5 percent by weight of fatty acid esters in which (1) the fatty acids contain from about 10 to about 18 carbon atoms; and (2) about 50 percent by weight or more of such fatty acids are composed of 2-hydroxydodecanoic acid and 3-hydroxydodeconoic acid. It follows, therefore, that the deproteinlzed a-emulsans are named "apo-&alpha;-emilsans" The name "ss-emulsans" defines those extracellular microbial protein-associated lipopolysaccharides produced by Arthrobacter Sp. ATCC 31012 and its mutants in which the lipopolysaccharide components (i.e. without the associated protein) are completely N-acylated and partially 0-acylated heteropolysaccharides ade up of major amounts of D- galactosamine and an aminouronic acid, the lipopolysaccharide components containing less than 5 percent by weight of fatty acid esters in which (1) the fatty acids contain from about 10 to about 18 carbon atoms; and (2) less than 50 percent by weight of such fatty acids are composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid. The deproteinized ss-emulsans are named "apo- Semulsans". The name "t,-emulsan" defines the O-deacylated extracellular protein-associated microbial polysaccharides obtained from the emulsans, the protein-free components of such 4)-emulsans being completely N-acylated heteropoly ,saccharides made up of major amounts of D-galactosamine and an aminouronic acid and containing from 0 to 1 percent of fatty acid esters in which, when present, the fatty acids contain from about 10 to about 18 carbon atoms. These protein-free components are named "apo-t-emulsans", regardless of how they are prepared. The name "proemulsans" defines the deproteinized O-deacylated extracellular microbial poZysaccharide in which the poly [ D-galactosamine/aminouronic acid ] biopolymers are characterized by (1) none of the hydroxy groups being acylated; and (2) from none to all of the amino groups being acylated. The proemulsans have no emulsifying activity under the standard assay techniques described below. From the data described herein, it is now known that the bioemulsifiers which were inherently formed in the experimental work previously published concerning the growth of RAG-1 on crude oil or hexadecane were ss-emulsans +,in which the lipopolysaccharide contained from 2 to 3 percent by weight of fatty acid esters. The ; 6-emulsans, therefore, have been given the common name "protoemuls nst', the prefix of which is derived from the Greek word EpOTO meaning "first". The a-emulsans have been given the common name "neoemulsans", the prefix being derived from the Greek word ncos meaning "new". Because the t-emulsans have only about one-half the emulsifying activity of the a-emulsans, the t-emulsans have been given the common name "pseudo emulsans". As used herein, the term "AcEnetohacter Sp. ATCC 31012 or its mutants" refers not only to the organism (i.e., strain RA G-1) described below in Section 6.1 and to its spontaneous and chemically- and physically-induced mutants and recombinants which produce emulsans, but to all microorganisms (whatever the genus) derived by using recombinant DNA techniques to insert genetic information from strain RAG-i and such mutants which are responsible for the production of the bioemulsifiers into the Based genetic code of such "recombined" microorganisms such that they are capable of biosynthesizing a-emulsans or -erulsans (or the apoemulsans), depending upon the primary assimilable carbon source and the conditions used to qrow the organism. 5. BELIEF DFSCRIPTION OF THE DWIb'GS To more fully comprehend the invention, reference should be made to the accompanying drawings, in which FIG. 1 is a graphical representation of the standard emulsifier assay described below in Section 6.4.1, showing the relationship between the amount or emulsification which is obtained with gas-oil and with 1:1 (v/v) mixture of hexadecane/2-methylnaphthalene as a function of the emulsan concentration; FC. 2 is a graphical representation of the extracellular production of a a-emulsan during growth of Acineto- bacter Sp. ATCC 31012 on an ethanol medium, showing the relationship of the growth of the organism in such medium, the production of the bioemulsifier during such growth/ and the change of p during such growth, all as a function of time; FIG. 3 is a graphical representation of the extracellular production of ss-emulsan durinq growth of Acinetobacter Su. ATCC 31012 on a hexadecane medium, showing the relationship of the growth of the organism in such medium and the production of the bioemulsifier during such growth, both as a function of time; ; FIG. 4 is a graphical representation of the changes which occur on acid hydrolysis of apo-a-emulsan, showing the relationship between the weight percent of reducing power of the acid-hydrolyzed deproteinized O-lipoacyleted heteropolysaccharide as a function of the duration of hydrolysis; FIG. 5 is a graphical representation of the relationship of the reduced viscosity of apo-a-emulsan as a function of ionic strength; FIG. 6, which is subdivided into FIGS. 6A an 6B, is a graphical representation of the kinetics of the emulsan-induced emulsification of gas-oil, showing the relationship between the emulsification of varying concentrations of gas-oil as a function of time for a given concentration of the bioemulsifier; ; FIG. 7 is a graphical representation of the relationship between the amount of emulsificaiton which is obtained 60 minutes after mixing in the emu ] san-induced emulsification of gas-oil as a function of gas-oil concentration for a given concentration of the bioemulsifier; FIG. 8 is a graphical representation of the re Jaticnship between the amount of emulsification which is obtained in the emulsan-induced emulsification of gas-oil as a function Ph in fresh water and sea water in the presence and absence of magnesium ions. FIG. 9 is a graphical representation of the relationship between the amount of emulsification which is obtained in the emulsan-induced emulsification of gas-oil as a function of salt concentration; FIG. 10, which is subdivided into FIGS. 1 OA and lOB, is a graphical representation of the relative stabilities of emulsan-induced emulsions of gas-oil, showing the relationship between percentage change in emulsification as a function of standing time of the emulsion for a given concentration of bíoemulsifier and varying weight ratios of yas-oil/bioemulsifier; ; FIG. 11 is a graphical representation of the rate at which emulsified oil droplets rise as a function of the weight ratio of gas-oil to bioemulsifier for given concentrations of the bioemulsifier; FIG. 12 is a graphical representation showing the relationship between the interfacial tension of nalkanes in sea water containing a given concentration of emulsan as a function of n-alkane chain length; FIG. 13 is a graphical representation showing the relationship of the amount of emulsification which is obtained in the emulsan-induced emulsification of various straight and branch chain alkanes as a function of carbon number of such alkanes; ; FIG. 14 is a graphical representation showing t relationship of the amount of emulsification which is obtained in the emulsan-induced emulsification of various alkylcyclohexanes as a function of carbon number of suc alkylcycloalkanas; FIG. 15 is a graphical representation showing the relationship of the amount of emulsification which is obtained in the emulsan-induced emulsification of various alkyl-substituted benzenes as a function of carbon number of such alybnzes; ; FIG. 16 is a graphical representation showing the relationship of the amount of emulsification which is obtained in the emulsan-induced emulsification of mixtures of hexadecane and a particular methylnaphthalene as function of the volume percent of hexadecane in such mixtures; FIG. 17 is a graphical representation of the kinetics of adsorption of emulsan on bentonite, showing the relationship between the amount of emulsan remaining in solution as a function of time after a given concentration of emulsan is shaken with a given ampunt of bentonite; and FIG 18 is a graphical representation of the kinetics of bentonite flocculation by emulsan, showing the relationship between the amount of clear upper layer which appears during sedimentation as a function of time when a given amount of bentonite is dispersed in a stan dardized control solution containing no added bioemulsifier and in the sane solution containing a given concentration of emulsan and both dispersions are allowed to settle. 6. PRODUCTION OF a-EMULSANS AND APOci-EMULSANS -Emulsans may be produced by aerobically growing Acinetobacter Sp. ATCC 31012 or a mutant thereof an aqueous fermentation medium which contains (a) a growth sustaining amount of a utilizable carbon source selected from ethanol or one or more fatty acid salts on which te organism will not only grow but will also produce the desired high-ester a-emu3san rather than the low-ester -emulsan; ; (b) greater than growth-sustaining amounts of least one assimilable nitrogen-containing compound Q growth-sustaning amounts of at least one assimilated phosphorous-containing compound to furnish these essential nutrients to the organism; and (c) from about 1 to about 100 mM of a divalent cation, such as magnesium, calcium or manganese, which faust be added to the fermentation medium it not present. Apo-&alpha;-emulsans, in turn, are produced by deprsteinization of the a-emulsans in such manner that the lipoheterpolysaccharide does not undergo degradation. The fermentation process may be conducted with a mastic or annual control in batch or continuous fermenters, using either fresh water or sea water media. Selection of suitable fermentation equipment may be made rom designs engineered to give the most efficient oxygen transfer to the biomass at lowest operating cost. In addition to the stirred tank fermenters, other types of fermenters may be used, such as thin channel fermenters, tubular loop fermenters, film fermenters, recirculating tower fermenters, deep shaft fermenters, and jet fermenters, the most important criteria being efficiency in the fermentation process, especially with respect to oxygen transfer and power consumption. Some of the more important process parameters for the production and purification of a-emulsans and apo-a-emulsans are discussed in more detail below. - 6.1. ACINETOBACTER SP. ATCC 3it12 The microorganism used to produce both neoemulsans and protoemulsans from utilizable carbon sources is Acinetobacter Sp. ATCC 31012 (also known as strain RAG-i), which has been deposited previously with the American Type Culture Collection, Rockville. !aryland. This organism, which has been described by A. Reisfeld et al., Appl. microbial., 24, 363 (1972) as well as by United States patent No. 3,941,692, has the following characteristics: During the exponential growth phase the cells appear mostly Gas irregular short rods, 0. tc 1.2 by 1.5 to 3.0 mcm tmcm = 10 6 m). The cells occur often as Vshaped pairs, indicating snapping division. Occasionatll, the rods are slightly bent or swollen. Coccoid cells, approximately 1.2 mcm in diameter, are characteristic of stationary phase cultures. The cocci are gram-positive; the rods are gram-negative. Agar colonies: circular, glistening and smooth, up to 5.0 mm in diameter; gelatin is liquified; starch is not hydrolyzed; indole and hydrogen peroxide are not produced; nitrites are produced from nitrate only when the cells are grown in citrate medium containing potassium nitrate; urease is not produced; catalase-positive; aerobic; hemolysis of rabbit blood agar; citrate can serve as the sole carbon and energy source; no acid from glucose, cellulose, maltose, lactose, rhamnose, sucrose or mannitol; optimum temperature 30' to 35' C. The amount of inoculum used to initiate the fermentat ion will be dependent upon the type of fermentation equipment used. For optimum results in batch-type stirred fermenters, growth should be initiated with late exponential cultures grown under similar fermentation conditions, preferably in an amount from about 1% to about 58 (v/v) of the fermentation medium. 6.2. FERMTIO MEDIA 6.2.1. UTILiZABLE CARBON SOURCES Even though it has previously been reported by . Horowitz et al., Appl. Microbiol., 30, 10 (1975), that strain RAG-1 will grow on many different carbon compounds on sea water agar media supplemented with the carbon source, such growth has no relationohip with whether or not the organism will produce any type of Acinetobacter bioemulsifier (which, when produced, usually occurs during the exponential growth phase), much less the high-ester a-emulsans. Moreover, even in those instances where the organism does produce extracellular lipopolysaccharides, there does not appear to be any correlation between the structure of the utilizable carbon source and what type of extracellular lipopolysaccharide will be biosynthesized from such carbon source, whether the high-ester remulsans or the low-ester S-emulsans. For example, growth of Acinetobacter g. ATCC 31012 on ethanol, sodium palmitate or dodecane results in the formation of a-emulsans with each such carbon source, with ethanol media yielding a-emulsans with the highest ester content in the lipoacyl portion of the lipoheteropolysaccharide, while growth of the organism under substantially identical conditions using pentadecane, hexadecane or heptadecane results only in the formation of 6-emulsans. In general, where a utilizable carbon source can be transferred into a-emulsans by the organism, the total yield of the extracellular lipopolysaccharide per liter of culture medium will be greater than when the organism produces ss-emulsans from a different carbon source. In the present invention, a-emulsans maybe produced by growing Acinetobacter Sp. ATCC 31012 or its mutants on an aqueous fermentation medium in which ethanol or one or more fatty acid salts are the primnrR, aFsimil8m)e carbon source. Such fatty acid salts include the assi.flila·le saturated fatty acids, such as decanoic acid (capric acid), dodecanoic acid (lauric acid), tetradecanoic acid (myristic acid), hexadecanoic acid palmitic acid) and octadecanoic acid (stearic acid); unsaturated C10 to C18 fatty acids, including monoethenoid and diethenoid fatty acids; hydroxysubstituted fatty acids, such as 2-hydroxydodecanoic acid, 3-hydroxydodecanoic acid and 12-hydroxyoleic acid (ricinoleic acid). In addition, mixtures of fatty acids may be used, such as the mixed fatty acids derived from saponification of lard, soybean oil, peanut oil, cottonseed oil, sunflower oil, coconut oil, castor oil, palm oil, linseed oil, and various fish oils or marine mammal oils. a -Emulsans produced by aerobically growing Acinetobacter Sp. ATCC 31012 on media containing ethanol or fatty acid salts are unusually efficient bioemulsifiers, exhibiting a high degree of specificity in emulsifying those hydrocarbon substrates (such as crude oils, gas-oils and Bunker C fuel oils) that contain both aliphatic and aromatic or other cyclic components. For optimum results in batch-type tire fermenters, the initial media should e.g. contain from about 1% to about 5% by weight of one or more fatty acid salts, with make-up fatty acid salt or salts added during the fermentation at a rate sufficient to sustain maximum growth and a -emulsan production, since the production of n -emulsans by the organism has been found to occur during the growth phase. 6.2.2. ADDITIONAL NUTRIENTS Maximum growth of Acinetobacter Sp. ATCC 31012 on a utilizable carbon source to produce a -emulsans requires more than growth-sustaining amounts of one or riiore assiiilabl nitron-containing compounds to furnish this essential nutrient to the organism to enable the organist to grow and to produce the biopolymer, which contains major amounts of amino sugars. Additionally, pnosphorus-cdntaining compounds are also essential nutrients. Suitable sources of available nitrogen include aiu salts, such as ammonium sulfate or ammonium chloride; nitrates, such as ammonium nitrate or sodium nitrate; or organic sources of available nitrogen, such as urea or soybean meal. Suitable sources of available phosphorous include dibasic potassium phosphate, monobasic potassium phosphate and the like. In addition, liquid fertilizers, such as 12-6-6 or 8-8-8, may serve as a source of nitrogen and phosphorous nutrients for the growth of Acinetobacter Sp. ATCC 31012. 6.2.3 DIVALENT CATIONS As shown below in the data set forth in Section 8.2, the emulsifying activity of both types of Acinetobacter bioemulsifiers is dependent above pH 6 upon divalent cations, such as magnesium ions, calcium ions or manganese ions. These divalent cations are present in sea water or "hard" water when fermentation media are prepared from such sources. When "soft" fresh water or distilled water are used to prepare the fermentation media, then small amounts of one or more salts of a divalent cation should be added to the fermentation media, the ccLentsati,onpiefetab1y being such that the resultant culture media will contain from about 1 to about 1.00 mM (and preferably from about 5 to about 40 mM) of at least one divalent cation. 6.3. FERMENTATION PROCESS CONDITIONS Maximum growth of Acinetobacter Sp. ATCC,31012 upon utilizable ethanol or fatty acid salt carbon sources to produce a-emulsans requires selection of the best conditions of aeration, agitation, temperature and pH under which the highest possible oxygen transfer can be obtained consistent with the physiology of the organism. Discussed below are the best conditions which have been found for consistently producing high yields of emulsans from ethanol or sodium palmitate media in conventional 60-liter stirred fermenters. These conditions probably will undergo subtle or pronounced changes to obtain higher yields upon large-scale production in fermenters specifically designed or adapted to give more efficient oxygen transfer at the lowest power consumption. Subsequent work on optimizing the process will, of course, focus on (a) consumption of the substrate, which is a function of the physiology of Acinetobacter Sp.-ATCC 31012 and its mutants; (b) consumption of oxygen, which is a function of oxygen diffusion to the cells which, in turn, will be influenced (i) by making the surface through which the diffusion occurs as large as possible (i.e., dispersing the gas phase as finely as possible in the liquid phase to create a large gas hold-up), (ii) by increasing the driving force of the diffusion (such as by increasing the pressure in the fermenter or by using oxygen-enriched air), and (iii) by allowing the diffusion constant to be as high as possible (i.e., by minimally decreasing the diffusion constant by the use of chemical antifoam agents); and (c) exothermic heat production, which necessitates a properly designed cooling system on scale-up. 6.3.1. AERATION Using 60-liter stirred fermenters with the fermentation medium and process conditions described below in Fraction 13.1, maximum production of a-emulsans occurs when 15 liters of air per minute are passed t.rough the 40 liters of fermlentation medium, which corresponds to an oxygen flow rate of 189.6 millimoles per liter per hour. This oxygen flow rate is not limiting but can, if necessary; be increased to as high as 700 millimoles per liter per hour, or even higher, with the more efficiently designee fermenters. 6.3.2. AGITATION To promote maximum oxygen diffusion to the cell mass, the fermentation media must be agitated either by stirring or circulating the media through the fermenter, depending upon the type of fermentation equipment emplQ'ed. Using 60-liter stirred fermenters with the fermentation medium and other process conditions described below in Section 13.1, maximum production of a-emulsans occurs when the medium is agitated at a rate of 250 rpm. This value is not limiting but will be varied in the more efficiently designed fermenters to achieve maximum oxygen transfer at the lowest power consumption. 6.3.3. TEMPERATURE AND pH Although the fermentation process may be conducted over a wide range of temperatures, best results have been obtained in the production of emulsans when the fermentation is conducted at 30 C. The pH of the fermentation medint preferably liquid he maintained beeeen 6 and 7, and preferably between 6.2 and 6.7 during the exponential growth phase, which necessitates the addition of sufficient base (preferably ammonia). 6.3.4. DEFAMING Stirred-tank fermentations of Acinetobacter Sp ATCC 31012 on utilizable fatty acid carbon sources to produce a-emulsans invariably are accompanied by foaming problems, which diminish the realizable yield of the extracellular lipopolysaccharide. Although many types of chemical defoamers may be used in the fermentation media, great care must be taken when adding chemical defoaming agents to keep the diffusion constant as high as possible. Using the 60-liter stirred fermenters with the fermentation medium and other process conditions described below in Section 13.1, maximum production of a-emulsans occurs when there were automatic pulse additions (whenever foam levels reached a predetermined height) of a silicone defoamant, preferably Dow-Corning 525 (sterilizable), diluted 1.8. Upon scale-up of the fermentation process, it is expected that a combination of chemical and mechanical methods will give optimum results in defoaming the nutrient solutions on which remulsans will be produced from Acinetobacter Sp. ATCC 31012 and its mutants. 6.4. EXTRACELLULAR PRODUCTION OF EMULSANS Data is presented below with respect to both types of extracellular lipopolysa,ccharides (a -emulsans and Semulsans) produced by Acinetobacter Sp. ATCC 31012 so that the similarities as well as differences between these biopolymers may be understood. Unless the particular type of extracellular lipopolysaccharide produced by the organism is identified by name, the phrase "Acinetobacter bioemulsifier" refers collectively to both a -emulsans and 6-emulsans. 6.4.1. STANDARD ASSAY FOR EMULSIFYING ACTIVITY In order to study the kinetics of bioemulsi""er production by Acinetcnacter Sp. ATCC 31012 and tn cnmpare the emulsifying activities of a -emulsans and B -em51=ans, a series of simple sensitive assay: for these bioemulsifiers were deve1oed. These assays were based upon the large increase in turbidity of a mixture of oil and water arising from the emulsion of the hydrocarbon in the aqueous phase. The first assay involved the emulsification of gas-oil in sea water under standardized conditions and subsequent measurement of turbidity. When it was found that sea water could be replaced in the assay procedure with dilute solutions of magnesium salts (cf/ Section 8.2), a second assay was developed involving emulsification of gas-oil in 10 m of magnesium sulfate at pH 7.2. Finally, after it was found that the bioemulsifiers exhibited a degree of specificity toward different classes of hydrocarbon substrates (cf/ Section 9), totally defined conditions were developed using a mixture of hexadecane and 2-methylnaphthalene in place of gas-oil and buffered magnesium sulfate (or magnesium chloride) in place of sea water. Each assay technique consisted of adding hydrocarbon (0.05 ml of gas-oil or 0.1 ml of 1:1 (v/v) hexadecane/2-methylnaphthalene) to 7.5 ml of filtered sea water or 7.5 ml- of Tris-Mg buffer l20 mM tris-(hydroxy methyi)aminomethane hydrochloride, pH 7.2, supplemented with 10 mi': magnesium sulfate] containing 1 to 25 units of bioemç1sifier per ml (about 3 to 75 mcg/ml of bioemulsifier) in a 125 ml flask. After reciprocal shaking (150 strokes per minute) for one hour at 26 C., contents of the flask were transferred to Klett tubes for measurement of turbidity in a Klett-Summerson colorimeter fitted with a green filter. Appropriate dilution were made in water so that the final readings were between 30 and 150 Klett units, and values for Klett units reported as final readings times the dilution Values for controls containing no blnem.ulsifier (5 to 20 Itt units) were subtracted. One unit of bioemulsifier per ml is defined as that amount of activity which yields 100 Klett units using 0.1 ml of 1:1 (vj) hexaJcca..e/2-..i^thylnaphthalene and 7.5 ml of Tris-Mg buffer. Specific Emulsification Activity (or specific activity) is units per m of bioemulsifier, dry weight basis. FIG. 1 graphically illustrates standard curves obtained when all three assay techniques were applied to an a-emulsan produced by growing Acinetobacter Sp. ATCC 31012 at 30 C. in a reciprocally shaken flask on a medium containing 1.08; (v/v) ethanol, 0.125% urea, 0.125 magnesium sulfate lMgS04.7H20 ] , 0.0002% ferrous sulfate [ FeSO4.7H2O), 0.001% calcium chloride (anhyd), 0.0258 dibasic potassium phosphate, and 0.2 M Tris HCl buffer, pH 7.4. The preparation of a-emulsan used in preparing such curves had a Specific Emulsification Activity of 330 units per mg. Curve 1-A represents the relationship between the amount of emulsification between'0.05 ml Gach-Saran gasoil and 7.5 ml of filtered sea water; Curve 1-B represents the relationship between the amount of emulsification between 0.05 ml Gach-Saran gas-oil and 7.5 ml,Tris-Ma-- buffer; and Curve 1-C represents the relationship between the amount of.emulsification between 0.1 ml 1:1 (v/v) hexadecane/2-methylnaphthalene and 7.5 ml Tris-Mg buffer, all as a function of a-emulsan concentration. Each point in FIG. 1 represents the average of 3 to 4 determinations. These standard curves were then used to determine the emulsifying activity of preparations of crude and purifies emulsans (a-emulsan, S-emulsan and the semi-synthetic -emulsan) and apoemulsans (apo-a-emulsan, apo-b-enuuisa and apo-*-erulsan). Characterization of a particular Acinetobacter bioemulsifier as an a-emulsan or a a-emulsan is based on chemical analysis of the fatty acid esters contained in the lipoacyl portions of the protein-extracted lipopolysaccharides. 6.4.2. EXTRACELLULAR PRODUCTION OF &alpha;-EMULSANS Measurement of extracellular emulsifying activity was determined at different stages of growth of Acinetobacter Sp. ATCC 31012 in an ethanol medium, the fermentation conditions being identical to those used to prepare the a-emulsan used for the standard assay tests. Growth was estimated by turbidity using a Klett-Summerson colorimeter fitted with a green filter or a Gilfor Spectrophotometer (Model 240). One hundred Klett units of exponentially growing Acinetobacter Sp. ATCC 31012 correspond to an absorbance at 620 nm (1-cm light path) of 0.816 and a biomass of 0.37 g per liter (dried at 90 C. for 16 hours). FIG. 2 shows the relationship between the growth of Acinetobacter Sp. ATCC 31012 on the ethanol medium, the production of the bioemulsifier fi -emulsan) during such growth, and the change of p during such growth, all as a function of time. Although these data are limited to the production of wemulsan in a shaking flask fermentation with a particular ethanol medium, FIG. 2 illustrates the general rule that the production of a-emulsan occurs during the growth period. Similar data have been obtained on the growth of Acinetobacter Sp. ATCC 31012 on e sodium palmitate medium. 6.4.3. EXTRACELLULAR PRODUCTION OF B-EULSAS Measurement cf oxtracellular emulsifying activity was also determined at different stages of growth of Acinetobacter Sp. ACC 31012 in a hexadecane media, the medium and termentation conditions being identical to those used to prepare the S-emulsan used for the standard assay tests except that 0.28 (v/v) hexadecane medium was used in place of ethanol as the carbon source. Viable cell number was determined by spreading 0.1 ml of an appropriate dilution on ACYE agar, which contained 0.5e sodium acetate, 0.1% yeast extract (Difco), 0.1258 urea, 0.0258 dibasic potassium phosphate and 1.58 agar (Difco). Plates were incubated at 32 C. for 3 days. FIG. 3 shows the relationship between the grout of Acinetobacter Sp. ATCC 31012 on the hexadecane medium and the production of the bioemulsifier' (-emulsan) during such growth. The data contained in FIG. 3 is similarly limited to the production of ss-emulsan in a shaking flask fermentation with a particular hexadecane medium, and shows that the production of ss-emulsan also occurs during the growth period. 6.4.4. DISTRIBUTION OF EMULSIFYING ACTIVITY IN FRACTIONS OF GROWTH CULTURE After 40 hours of incubation of Acinetobacter Sp. ATCC 31012 in the ethanol medium and in the hexadecane medium ss described above in Sections 6.3.2 and 6.3.3, respectively, each culture was centrifuged at 10,COO x a for 15 minutes and the pellets washed once with Tris-Dv, buffer. The pellicle formed during centrifuqation of the hexadecane culture was removed, washed twice with broth medium before assaying for activity. Emulsifying activity in each fraction for the ethanol an hexadecane growth cultures was assayed by the standard assay techni a,ue described abcve in Section 6.4.1 and illustrated in FIG. 1. The results of such assays are sunarized in Table I. TABLE I Distribution of Emulsifying Activity in Fractions of Growth Cultures Fraction Emulsifier (units/ml) Ethanol Hexadecane Substrate Substrate Pellet 7 0 Supernatant fluid 23 14 Pell@cle The data contained in Table I show that over 75E of the activity was extracellular when ethanol was the substrate, while all of the measureable activity was extracellular when Acinetobacter Sp. ATCC 31012 was grown on hexadecane medium. The small amount of activity associated with the pellet-.fraction was variable, in certain cases no measureable cell-bound activity could be owny. Disruption of the pellet fractions by sonic oscillation did not release additional emulsifying activity. 6. 5. DEPROTEINIZATION Apoemulsans may be prepared by deproteinization of the particular emulsans, which technique was used to isolate and purify samples for the cnemical characterization of both Acinetobacter bioemulsifiers described below. The associated protein may be separated irom both bioewul- sifiers by the hot phenol extraction technique described by 0. Westphal et al. in the monograph edited by R. L. Whistler, entitled "Carbohydrate Chemistry", Academic Press, Inc., New York, pp. 83-91. Alternatively, the protein may be removed enzymatically by proteolytic digestion. 6.6. ISOLATION AND PURIFICATION The extracellular protein-associated lipopolysaccharides produced by Acinetobacter Sp. ATCC 31012 and their respective deproteinized derivatives may be isolated and purified by various procedures, including selective precipitation, selective-solvent extraction or partitioning or selective adsorption onto a solid adsorbant followed by subsequent elution or extraction. For many industrial uses, isolation and purification of the Acinetobacter bioemulsifiers is not necessary, since the cell-free growth media may be used directly. For the purposes of determining their respective structures as well as their chemical and physical properties, particu larly with respect to emulsifying activity, the -emulsans and ss-emuisans produced by Acinetobacter Sp. ATCC 31012 have been isolated and purified. Three different procedures have been followed, including (a) heptane partitioning of the crude extracellular lipopolysaccharide from the fermentation medium, followed by extraction of impurities from the heptane-partitione biopolymer and subsequent work-up; (b) precipitation of the extracellular lipopolysaccharide by ammonium sulfate, followed by work-up of the precipitate; and (c) precipitation of the extracellular lipopolysaccharide by a detergent quaternary ammonium cation followed by work-up of the precipitate. Each of these techniques is equally applicable to the isolation and purification of the apo-a-emulsans and the apo-8-emulsans. 6.6.1. HFPTANE PARTITIONING Because the Acinetobacter bioemulsifiers exhibit specificity with respect to the structurally different types of hydrocarbon substrates which may be emulsified (cf/ Section 9), certain water-immiscible hydrocarbons may be used to selectively extract the extracellular lipopolysaccharide from the fermentation media without creating a stable emulsion. By way of illustration, heptane extraction of the cell-free culture medium from which ether-extractibles had been removed suspended over 90% of extracellular lipopolysaccharide at the heptane/water interface. After evaporation of the heptane, and preferably fther solvent extraction with ether, the resultant product is a viscous syrup which can be dissolved in 508 aqueous methanol, the impurities removed by dialysis and the remaining material recovered by lyophilization. In a typical example using this heptane partitioning technique, a puritied S-emulsan was prepared which was characterized by a specific activity of 5 units per mg. 6.6.2. AMMONIUM SULFATE PRECIPITATION The addition of ammonium sulfate to the fermentation broth has been used to fractionally precipitate the extracellular lipopolysaccharides from the culture medium, from which t're concentrate may be recovered and further treated to remove impurities. By way of illustration, addition of ammonium sulfate to cell-free supernatent fluids has resulted in the precipitation of substantially all of the extracellular lipopolysaccharides when the concentration of ammonium sulfate is increased from 30% saturation to a final concentration of 408 saturation. The resulting precipitate, which may be collected by centrifugatlon, has been extracted by ether to remove impurities, dialyzed against water and lyophilized, yielding the purified extracellular lipopolysaccharide. In a typical example using this ammonium sulfate precipitation technique, a purified semulsan was prepared which was characterized by a specific activity of 330 units per mg. 6.6.3. QUATERNARY AMMONIUM PRECIPITATION Because the extracellular lipopolysaccharides produced by Acinetobacter Sp. ATCC 31012 were found to be anionic biopolymers, a procedure was developed to precipitate the anionic biopolymer with a cationic detergent, such as cetyltrimethyl ammonium bromide, from which precipitate the detergent cation could be separated while leaving the purified extracellular lipopolysaccharide. For example, the addition of cetyltrimethyl ammonium bromide to an aqueous solution of a-emulsan immediately forms a precipitate which is recoverable by centrifugation or flltratioll. This precipitate is soluble in 0.1 M sodium sulfate, from which solution cetyltrimethyl ammonium ivdide precipitates upon addition of potassium iodide, leaving the a-emulsan in the supernatant fluid. Dialysis of this supernatant fluid against distilled water followed by lyophilization has yielded highly purified samples of Q-emulsan as a white solid, with a specific activit of 30 units per mg. 7. CHEMICAL AND PHYSICAL PROPERTIES OF EMULSANS AND APOEMULSANS Chemical and physica] characterization of emulsans and apoemulsans were measured on samples which had been purified to apparent homogeneity, from which characterization conclusions were reached on the structure of these unique extracellular lipopolysaccharides. Such information is necessary to give a better understanding of the relationship between the molecular structure of this class of bioemulsifiers and their specificity in emulsify ing various hydrocarbon substrates. 7.1. PREPARATION OF SAMPLES FOR ANALYTICAL CHAKACTEIZATION 7.1.1. PREPARATION' OF EMULSAN SAMPLES The emulsan samples used for chemical and physical characterization were prepared by aerobically growing Acinetobacter Sp. ATCC 31012 on an ethanol medium ('-emulsan) or a hexadecane medium (E -emulsan) and were purified by precipitation between 30-40t ammonium sulfate saturation, followed by extraction with ether, dialysis against distilled water and lyophilization, as described more fully in the example set forth below in Section 13.8. Some samples of a -emulsan were further purified by employing the cetytrimethyl ammonium bromide precipitation technique, as described more fully in the example set forth below in Section 13.11. 7.1.2. PREPARATION OF APOEMULSAN SAMPLES The apoemulsan samples used for chemical and physical characterization were prepared by hot phenol extraction of the associated protein moiety from the emulsan samples. The deproteinization procedure, which is described more fully in the example set forth below in Sections 13.4 and 13.5, involved adding a dilute solution (5 mg/ml) of emulsan preheated to 65 - 68-C. to an equal volume of 909 phenol at 65-C., stirring the mixture for 15 minutes while maintaining the temperature at 65we., and then cooling the mixture to 10 C. in an ice bath. The resulting emulsion was then centrifuged to separate the denatured protein in the phenol phase from the apoemulsan in the aqueous phase. After transferring the viscous aqueous phase to a flask, the phenol layer and phenol/ water interface were extracted three more times with water, following which the combined water extracts were dialyzed extensively against several changes of distilled water and then freeze-dried, yielding 85% by weight of apoemulsan based on the weight of the emulsan. All of the emulsifying activity was in the recovered emulsan. None of the emulsifying activity was in the denatured protein fraction. 7.1.3. AMMONIUM SULFATE FRACTIONATION OF APO-&alpha;-EMULSAN To assure homogeneity of the apo-&alpha;-emulsan, the deproteinization procedure was repeated on another sample of eemulsan which had been prepared by aerobicallv a-Lowing Acinetobacter Sp. ATCC 31012 on an ethanol medium and which had been purified by precipitation between 30-407 ammonium sulfate fractionation, -followed b extraction with ether, dialysis against distilled water and lyophilization. After three phenol extractions, the combined water extracts were extracted four times with an equal volume of ether to remove residual phenol. Following evaporation of any retained ether, the viscous aqueous phase as cooled to 5*C. and brought to 32.5% ammonium sulfate saturation. After standing for one hour at 5¯C., the clear translucent precipitate was collected at centrifugation at 5,000 x g for 30 minutes at 5-C. The procedure was repeated to obtain a slightly turbid second precipitate between 32.58 and 35E ammonium sulfate saturation and another small precipitate between 358 and 40% ammonium sulfate saturation. No additional precipitate formed between 40% and 60% saturation. Each of the precipitates was dissolved in water and was then dialyzed at 2-50C. successively against distilled water, 0.05 N hydrochloric acid for 24 hours and double distilled water, following which each of the resulting solutions were freeze-dried. Over 99% of the emulsifying activity of the apo- cc-emulsan was found in the two fractions which precipitated between 30% and 35 ammonium sulfate saturation. These two fractions contained similar specific activities and exhibited substantially the same chemical composition. In addition, both fractions were homogeneous when examined by immunodiffusion against antibodies prepared against ss-emulsan, each giving a single identical band upon Ouchterlony two-dimensional diffusion. ccordngly, the two fractions were combined for certain of the chemical and physical characterizations, the combined fractions when used being identified herein as "apo-a-emulsan-WA". 7.1.4. QUATEKARY AMMONIUM SALT PRECIPITATION OF APO-a -EMULSAN To cross-check the analytical data on apo- -emul- san-WA, another highly purified sample of apo-a-emulsan was prepared using '(1) the identical hot phenol extraction of another sample of a-emulsan which had been prepared by aerobically growing Acinetobacter g. ATCC 31012 on an ethanol medium, followed by (2) cetyltrimetiyl ammonium bromide precipitation of the resultant apo-a-emulsan, dissolving the precipitate in 0.1 M sodium sulfate, and addition of potassium iodide to the solution to precipitate cetyltrimethyl ammonium iodide. The supernatant fluid contained the apo-a-emulsan. Extensive dialysis of this supernatant fluid against distilled water followed by lyophilization yielded a highly purified apo-a-emulsan which was designated as "apo-a-emulsan-CTAB". 7.2. CHEMICAL CHARACTERIZATION 7.2.1. CHEMICAL COMPOSITION OF EMULSANS AND APOEMULSANS Elemental analyses of a-emulsan and apo-a-emulsan, which were performed on samples of a-emulsan and apoa-emulsan-WA that had been dried to constant weight at 559C. in vacuo (the latter sample having released 12.7% water on such drying), are shown in Table II. TABLE II Elemetal ComDosition of Emulsan Sample 8 C % H % N % S % Ash a-Emulsan 41.72 6.95 7.74 0.7 13.8 Apo-a-emulsan-WA 46.70 7.01 6.06 0.0 The deproteinized sample (apo-a-emulsan-WA) con tained significantly less N, S and ash than emulsan. The C:N:H ratio of apo-&alpha;-emulsan-WA was calculated to be 9.0:1.0:16.1. No significant quantities ( < 0.5%) of phosphorous or halides were found in either sample. Functional op tests were positive for carboxyl and ester groups and negative for methoxy and ethoxy groups. The polymer contained less than 0.02 micromoles reducing sugar per mg,which was the sensitivity of the test employed. The nonreducing polymer was resistant to high temperatures in neutral and alkaline conditions. No emulsifying activity was lost at 100-C. for 2 hours in distilled water; 50% of the activity remained even after treatment in 1 N sodium hydroxide at 100"C. for 1 hour. Apo a-emulsan-WA was considerably more sensitive to acid, losing 50% of its emulsifying activity in 2 minutes at 100 C. in 1 N hydrochloric acid. Titration of apo-a-emulsan-WA (40 m/4 ml) between pH 2.5-10.5 showed a single inflection point, corresponding to pK' = 3.05 (identical to a standard sample of glucuronic acid). Apo--emulsan-WA consumed 0.24 micromoles periodate per mg (which would suggest the presence of a small amount of glucose in the polymer), which was subsequently esters mined to be due to a small amount of glucose present in an ammonium sulfate co-precipitated extracellular polysaccharide witch possessed no emulsifying activity. Periodate uptake ceased after two hours at 30 C., pH 4.5. The periodate treated material did no lose any emulsifying activity, further indicating that no glucose was present in the apo-a-emulsan. 7.2.2. ALKALINE HYDROLYSIS OF APOEMULSAN Two hundred milligrams of apo-a-emulsan-ltA were refluxed in 40 ml of 1 N sodium hydroxide for 4 hours, cooled, extracted three times with 40 ml ether, acidified to p 1-2 with concentrated hydrochloric acid, and extracted again three times with 40 ml ether. The acid-ether extracts were combined and dried in a tared flask, yielding 30 mg (158) fatty acids; extraction with ether prior to acidification yielded less than 2 mg dry material. Combining the weight recovery of fatty acid from the polymer (150 mcg/mg) and the 0-ester content '(0.65 micromoles/mg) yields an average equivalent weight of 231 for the fatty acids. 7.2.3. ACID HYDROLYSIS OF APOEMULSAN Preliminary hydrolysis studies were performed on apo-a-emulsan at 809C. and 1009C. in sealed tubes with concentrations of hydrochloric acid varying from 0.01-6.0 M. After removal of hydrogen chloride in vacuo, the products were examined for reducing power, amino sugars and by paper chromatography in n-butanol/pyridine/water (6:4:3, v/v) [Solvent A] and in n-propanol/ethyl acetate/ water (7:1:2, v/v) solvent B ] . FIG. 4 is a graphical representation of the changes which occur on acid hydrolysis of apo-a-emulsan. The weight percent of reducingpower is plotted against the duration of hydrolysis at 100C. at 0.05 M HCl (shown in the lower curve) at 5 M HCl (shown in the upper curve). Hydrolyses were performed in sealed tubes under nitrogen on 1 mg/ml samples ofapo-a-emulsan. As shown in FIG. 4, at 0.09 M hydrochloric acid at 100"C. there was a release of around 6% reducing sugar during the first hour, followed by a slower release of about 1% reducing sugar per hour for the next 2C hours. After 27-hour hydrolysis in 0.05 M HCl at 100C., chrómatography revealed the presence of two major reducing spots (subsequently identified as galactosamine and an aminouronic acid) and one minor component (subsequently identified as glucose). (N.B. - Analytical work done much later on CTAB-fractionated material indicates that the presence of glucose was due to an impurity which was coprecipitated during the ammonium sulfate fractionation of apo-cx-emulsan ] In addition, there were considerable amounts of incompletely hydrolyzed material (remaining near the origin). After 5-hour hydrolysis in 0.05 M HCl, only glucose was detected on the chromatograms. N-acetyiated derivatives of the amino sugars were never detected. Maximum amount of reducing sugar was obtained by hydrolyzing apo-a-emulsan in 5 M HCl, at 100"C. for 30 minutes. Even under these conditions significant amounts of emulsifying agent were incompletely hydrolyzed. Longer periods of hydrolysis resulted in further destruction of the sugars. The relative amount of amino sugars to glucose increased with time of hydrolysis due both to the slower release of amino sugars from the polymer and faster destruction of free glucose. Hydrolysis of samples of the ammonium sulfate fractionated apo-a-e:nulsan-WA showed the same chromatographic pattern as that of apo-a-emulsan; However, when this analysis was repeated on the sugars produced by hydrolysis of apo-a-emulsan-CTAB at 1009C. in 0.05 N and 5 N HCl for the same periods of time, no glucose was detected. Following hydrolysis in 5 M HCl at 100we. for 30 minutes, apo-a-emulsan-WA released 37.6% reducing sugar and 24.4% total hexosamines (in both cases, using galactosamine as the standard). 7.2.4. IDENTTFTCAl'JON OF SUGAR COMPONENTS Table III summarizes the data that led to the conclusion that the sugars produced by hydrolysis of ammonium sulfate fractionated apo-a-emulsan were D-glucose (minor), D-galactosamine (major) and an aminouronic acid (major). Unknown compound A did not separate from glucose in solvents A or B and yielded a positive glucose reaction directly on the paper. Unknown compound B migrated identically to galactosamine in solvent B, gave a positive Dcgalactose oxidase reaction and was converted to lyxose (RGlc=1,49 in solvent B) by ninhydrin degradation. Unknown compound C gave positive reactions for reducing sugar, amino sugar and carboxylate ion. Moreover, it was similar both in chromatographic behavior and in its reaction with the nitrous acid-indole test to 2-amino-2deoxyhexuronic acids. TABLE III Properties of Sugar Products of Hydrolysis of Amonnium Sulfate Apo-&alpha;-Emulsan Componenta RGlcb Positive reactionsc Standards: D-glucose 1.25 glucose oxidase D-galactose 1.22 galactose oxidase D-glucosamine 1.00 ninhydrin (purple), EM, glucose oxidase D-galactosamine 0.85 ninhydrin (purple), EM, galactose oxidase D-N-acetylgalactosamine 1.58 EM Acid hydrolysis products of apo-&alpha;-emulsan: A 1.25 glucose oxidase B 0.85 ninhydrin (purple), EM, galactose oxidase C 0.23 ninhydrin (greenish yellow, later b-lue), EM Obtained after 24 hour hydrolysis cf apo-a-emulsan in 0.05 M HCl aL 100"C. b/ Rate of movement of each sugar relative to glucosamine in solvent A. All components gave positive alkaline silver nitrate tests. Spot tests were determined directly on the chromatograms. EM is the modified Elson and Morgan reagent [R. W. Wheat in the monograph edited by E. F. Neufeld et al., "Methods in Enzymology", Vol. VIII, Academic Press Inc., New York, pp. 60-78. Based on all the evidence, therefore, it is virtually cerain that the polymer ts polytD-galactosamine/aminouronic acid3. Any glucose present is probably an impurity. 7.2.5. IDENTIFICATION OF FATTY ACIDS Usually, the esterfied fatty acid content of apo-a-e::ulsans derived from the deproteinizz- tion of a-emulsans prepared by aerobically growing Acinetobacter Sp. ATCC 3tO12 on an ethanol medium is in the range from about 7% to about 15%, corresponding to about 0.3 to about 0.7 micromoles per milligram of 0-substituted fatty acid esters in whizz the fatty acids have an average equivalent weight from about 200 to about 230. Alkaline hydrolysis, acidification and ether extraction of a-emul- san yields a mixture of fatty acids, the infrared spectrum of which exhibited absorption peaks at 3610 cm 1 (nonbonded O-H), 3500 cm 1 (bonded O-H), 1705 cm 1 (C=O) and 1050 cm (C-On). The NMR spectrum in CnCl3 indicated that the mixture consisted mainly of saturated and hydroxy-substiXuted fatty acids. Base hydrolysis of one gram of -emulsan was performed in 400 ml of 2.5% potassium hydroxide in 908 methanol under reflux for 4 hours. After removal of the methanol in vacuo, 500 ml of water were added. The clear alkaline solution was washed three times with 150 ml of ether, the ether discarded, and the aqueous solution acidified to pH 2 with hydrochloric acid. The acid solution was then extracted five times with 100 ml ether, the interphase in each extraction being set aside. The combined interphase fractions were treated with acetone to precipitate protein and polysaccharide. After removal of the precipitate by filtration and the acetone by distilla tion in vacuo, the aqueous phase was again extracted with ether. The combined ether extracts were dried over magnesium sulfate. Removal of the ether left 130 mg (13% yield) of a mixture of fatty acids. The methyl esters of the fatty acid mixture were prepared with diazomethane by standard techniques. Gas liquid chromatography of the methyl esters of the fatty acid mixture led to the separation of eleven peaks, nine of which were identified b comparison of retention volumes of pure samples of known structure. Table IV sets forth the relative retention volumes of the methyl esters of the fatty acids obtained from emulsan. TABLE IV Fatty Acid Methyl Esters Obtained from Ellld=Base=Hydrolygis a-Emulsan Peak No. Fatty Acid Relative Retention ¯¯¯¯¯¯¯¯¯ Methyl Ester Volume 1 Decanoic 0.17 2 Dodecanoic 0.29 3 Dodecenoic 0.34 4 Unidentified 0.48 5 Unidentified 0.61 6 Hexadecanoic 1.00 7 Hexadecenoic 1.14 8 2-Hydroxydodecanoic 1.30 9 3-Hydroxydodecanoic 1.69 10 Octadecanoic 1.94 11 Octadecerioic 2.16 Although the relative amounts of fatty acids will vary from sample to sample, usually, the two hydroxydodecanoic acids comprise from about 50% to about 70 of the aggregate fatty acids, with 3-hydroxydodecanoic acid usually predominating over 2-hydroxydodecanoic acid. Table V sets forth the fatty acid composition of the a-emulsan described above. TABLE V Typical Fatty Acid Composition of Emulsan Fatty Acid Per Cent of Total Fatty Fatty Acids Decanoic 11.4 Dodecanoic 23.0 Dodecenolc 2.4 2-Hydroxydodecanoic 9-Hydrcxydoaecancic 39.5 Hexadecanoi c 0.7 Hexadecenoic trace Octadecanoic 0.3 Octadecenoic trace Unidentified 12.0 The acetone-Precipitated polysaccharide remaining after O-deacylation of the a-emulsan by mild base hydrolysis was redissolved in water, dialyzed extensively against water, lyophilized and then subjected to acid hydrolysis for 6 hours at 98 C. in 5 M HCl. The aqueous hydrolysate was extracted with ether and the ether extract was treated by diazomethane to convert to methyl esters whatever fatty acids remained after such strong acid hydrolysis. Gas chromatographic analysis of this material revealed the-presence of methyl 3-hydroxydodecanoate as the only fatty acid. This showed that N-(3-hydroxy- dodecanoyl) groups were also present in temulsan. :7.3. PHYSICAL CHARACTERIZATION Preliminary experiments indicated that the purified a-emulsan was excluded by Sephadex G-100 and G-200 and did not pass an Amicon XM-30 filter. This data, coupled with the fact that apo-a-emulsan contained 1.5 micromoles of carboxylic groups per mg, suggested that the lipopolysaccharide was an anionic polymer. Additional data on physical characterization is set forth below: 7.3.1. INTRINSIC AND REDUCED VISCOSITY The intrinsic viscosities of the analytical samples of a-emulsan, apo-a-emulsan and apo-d-emulsan-V;S in 0.75 M liris buffer, pH 7.4, were 470, 505 and 750 cc per gm, respectively. With all three samples, reduced viscosity was independent of concentration between 0.05 and 1.0 m per ml. Exposure of 0.5 mg per ml apo-a-emulsan to sonic oscillations (Branson B12 sonifier, setting 8, 14 min) reduced the reduced viscosity to 420 cc per am. Exposure for an additional 20 minutes did not further reduce the viscosity. The viscosity of apo-a-emulsan as a function of ionic strength is shown in FIG. 5. Between 0.03-0.15 M NaCl, reduced viscosity decreased slightly from 515 to 480 cc per gm. The large increase in reduced viscosity at low ionic strengths is characteristic of polyelectrolytes and has been attributed to dilution of counterions. Specific viscosity was also measured as a function of pH using 0.05 M citrate-phosphate buffer (pH 3-7) and 0.05 iv, Tris HCl buffer (pH 6.8-8.5). Throughout the entire range (pH 3-8.5) the specific, viscosity of c'-emulsan remained at 480 + 50 cc per gm. 7.3.2. SEDIMENTATION VELOCITY ANALYSIS Sedimentation velocity analysis of 2 mg/ml of apo-&alpha;-emulsan-WA in 0.15 M NaCl showed a single broad band corresponding to an s20 = 6.06 x 10-13 sec or 6.06 S. The diffusion coefficient, D, also determined in the analytical centrifuge was 5.25 x 10-8 cm2 sec-1. The partial specific volume of the material, V, was 0.712 cm3 g-1. 7. 3. 3. ESTIMATION OF MOLECULAR WEIGHT Estimating the molecular weight of apo- -emul- san-WA from the equation, M=RTs/D(1-VP), where Ris the gas constant, T is the absolute temperature and P is the density of the solution, yields a weight average molec > 'ar wejohe of 9.76 x 105. alternatively, the molecular weight can be estImated using the determIned values for intrinsic viscosity, TI, sedimentation constant, S, and partial molar volume, V according to the equation of Scheraga and Mandelkern (J. 7.3.3. Ajn. Chew. Soc. r 75 179 (1953)]. The calculated viscosity average molecular weight for apo-&alpha;-emulsan-WA was 9.88 x 105. 7.3.4. SPECTRAL PROPERTIES The ultraviolet absorption spectrum of apo-aemulsan-WA (220-350 nm) showed no maxima. The infrared spectrum of apo-a-emulsan incorporated into a KBr pellet or nugol revealed the following groups: 3340 cm-1 (O-H), 2900 cm-1 (C-H), 1720 cm-1,weak (C=O), 1649 cm1 (amide I) and 1545 cm-1 (amide II). X-ray diffraction analysis of apo-a-emulsan, which was performed on a film formed by evaporation of a water solution of apo-a-emulsan, showed crystallinity. Table VI summarizes the 20 angles and d spacings measured for the X-ray diffraction pattern recorded with Ni filtered CuKa radiation. TABLE VI X-Ray Diffraction Analysis of Apo-&alpha;-emulsan 20 C d( ) I(rel.) 21.00 4.23 S 16.70 5.31 W 14.80 5.99 13.04 6.79 W 10.66 8.30 W 7.18 12.30 S 7.4. CONCLUSIONS ON STRUCTURE The foregoing data show that apo-a-emulsan is a highly acidic lipopolysaccharide with a molecular weight average close to one million. Molecular weight determine tion from sedimentation and diffusion data closely fit the value obtained from a consideration of sedimentation and viscosity measurements. In both cases the determined value for the partial molar volume of 0.712 cm3 gum 1 was used. The relatively high intrinsic viscosity, low diffusion constant and low sedimentation coefficient of the emulsifier indicate that the shape of apo-a-emulsan is highly asymmetrical. Using Simha's factor [C. Tanford, "Physical Chemistry of Macromolecules", John Wiley and Sons, Inc., New York, 1963, pp. 390-411] for the viscosity increment of rod-shaped ellipsoids indicates that apoo emulsan has an axial ratio of close to 100. Preliminary examination of the purified apo-a-emulsan by electron microscopy revealed thin fibers with length greater than 1000 . Apo-aemulsan is composed of major amounts of two amino sugars (D-galactosamine and an aminouronic acid) and a mixture of fatty acid esters in which the fatty acids (a) contain from 10 to 18 carbon atoms, and (b) possess an average equivalent weight from about 200 to about 230, about 50t or more of such fatty acids being composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid, with the latter hydroxy fatty acid predominating. T tration curves and infrared spectrum of the apo- cremulsan sample indicate that the amino sugars of the biopolymer are N-acylated. The aminouronic acid content of the apo-a-emulsan sample was estimated by acid-base titraticn of the biopolymer to be 1.5 microroles/mg. Assuming the aminouronic acid to be an N-acetylhexosamine uronic acid (M.Tr.. = 222), it would comprise 33% by weight of the biopolymer. Direct estimation of D-galactosamine content of the apo-a-emulsan sample is not rJ¯-ible St this time, since hydrolysis conditions necessary to release it from apoemulsan cause considerable decomposition of the amino sugar. Rough estimates (from intensities of reducing and ninhydrin positive materials on chromatograms) indicate that the amount of D-galactosamine is similar to the quantity of aminouronic acid. The total fatty acid ester content of the apo- -emulsan sample was 158 by weight with an average equivalent weight of about 231. Table VII summarizes the chemical composition of apo- -emulsan-A on the basis Ot all the data. TABLE VII Chemical Composition of Apo-&alpha;-emulsan-WA Apo-a-Emulsan-WA Component (%) D-galactosamine 20-30b Hexosamine uronic acid 33*3 D-glucoseC 5.2 Fatty acid estersd 15.0 Water 12.7 Ash 3.5 Calculated as N-acetylated amino sugar. B# Estimated from intensity of ninhydrin and reducing spots on chromatograms. / Probably present as an impurity In apo &alpha;-emulsan-WA. 'See Table V for typical fatty acid distribution. 7.5. VARIATIONS IN STRUCTURE Table VII summarizes the chemical composition of apo-a-emulsan-WA, which is a highly purified sample free of protein and nucleic acid and which appeared to be homogeneous by several criteria, namely (a) only a single band was found by Ouchterlony two-dimensional diffusion; (b) only a single component was observed by sedimentation velocity studies, using several concentrations of material; and (c) attempts to further purify the material by extrac tion or precipitation with organic solvents did not improve its specific activity or alter its chemical composition. Growth of Acinetobacter Sp. ATCC 31012 on a utilizable carbon source (such as ethanol, sodium palmitate or dodecane) to produce those bioemulsifiers which are characterized as eemulsans will yield products in which the O-lipoacylated heteropolysaccharide may deviate from the specific chemical composition for apo-a-emulsan- shown in Table VII, which sample was derived from an emulsan produced by growing Acinetobacter Sp. ATCC 31012 on an ethanol medium. Table VIII shows the differences between the emulsans prepared by growing the organism on ethanol and on s: -um palmitate, respectively. In each case, the fermentation media and conditions were identical except for the carbon source. TABLE VIII Emulsans Produced by Growing RhG-1 on Ethanol and on Sodium Palmjtate Carbon Yield a Specific % Amino % EsterC Source (units/ml) Activitya Sugarb (units/mg) Ethanol 190 146 12 10 Sodium Palmitate 111 116 13 9 a/ AnaiXses were performed on the crude extracellular fluid following extensive dialysis against water. Amino sugars were determined after hydrolysis in 6 N hydrochloric acid using galactosamine as the standard. Total ester cont-nt was determined using the hydroxamic acid test, taking the average equivalent weight of the fatty acid esters to be 230. Usually the N-acyl and partially O-acyl heteropolysaccharides in the a-emulsan or constituting the apo-a-emulsan produced by the process of the invention will be composed on a dry weight basis of from about 208 to about 35% by weight of D-galactosamine; from about 30t to about 358 by weight of hexosamine uronic acid; and from about 7% to about 19% by weight of fatty acid esters in which the fatty acids contain from about 10 to about 18 carbon atoms and are characterized by an average equivalent weight from about 200 to about 230, from about 50E to about 70% of such fatty acids being composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid. Although the ratio of 2-hydroxydodecanoic acid to 3-hydroxydodecanoic acid in the 0lipoacyl portion of the apo-a-emulsan (or apo-a-emulsan component if the product is an a-emu)san) may vary from about 1:4 to about 1:1, the 3-hydroxydodecanoic acid will predominate in those biopolymers which have a high Specific Emulsification Activity. 7.6. IMMUNOLOGICAL CHARACTERIZATION To immunologically characterize the Acinetobacter bioemuiFifiers produced by Acinetobacter Sp. ATCC 31012, rabbits were injected with 1 mg of Femulsan in 1 ml complete Freund adjuvant. The rabbits were bled 11 to 14 days later, from which sera a crude immunoglobulin fraction was obtained by ammonium- sulfate fractionation. Antibodies prepared against B-emulsan crossreact with in an identical fashion with a-emulsan, apo-&alpha;- emulsan, apo-ss-enulsan, *-emulsan (produced by mild base hydrolysis of a- or ss-emulsan) and proemulsan (produced by strong base hydrolysis of any of the fcregoing), indicating that both Acinetobacter bioemulsifiers (a-emulsan and ss-emulsan) and their various deproteinated and deacylated derivates have approximately the same polymer backbone, even though these classes of biopolymers are distinguished by fatty acid ester content as well as by differences in the distributions of fatty acids, the a-emulsans containing a larger amount and greater proportion of 3-hydroxydodecanoic acid ester than the ss-emulsans. 8. EMULSIFYING PROPERTIES Data are presented below with respect to the emulsifying properties of both types of extracellular lipopolysaccharides ( remulsans and ss -emulsans) produced by Acinetobacter Sp. ATCC 31012 so that similarities as well as differences between these biopolymers may be understood. As before, unless the particular type of extracellular lipopolysaccharide produced by the organism is identified by name, the phrase "Acinetobacter bioemulsifier" refers collectively to both classes of emulsans. Unless otherwise indicated, emulsifying activity was assayed in accordance with the standard assay technique descrit above in Section 6.4.1 using the standard curves shown in FIG. 1. 8.1. KINETICS OF EMULSAN-INDUCFD EMULSION FORMATION The rate of emulsification of gas-oil by purified cinetobacter bioemulsifier is summarized in FIG. 6, in which the numbers identifying each curve refer to the weight ratios of gas-oil/bioemulsifier. At fixed concentrations of bioemulsifier (0.25 mg in FIG. 6A and 0. ru in FIG. 6B, each in 7.5 ml of filtered sea water), using amounts of gas-oil varying from 4.5 to 582 ms and under the conditions (i.e., reciprocal shaking at 150 strokes per minute for 1 hour at 25 C.) of the standard assay technique, the rate of emulsion formation as well as the final turbidity were proportional to gas-oil concentration between 5 to 100 mg of gas-oil per ml. With 33 or 100 mcg/ml of bioemulsifier and concentrations of gas-oil exceeding 45 my/ml, half-maximum turbidities were reached in less than 5 minutes. When the bioemulsifier and gas-oil were allowed to interact at 250 C. for 2 hours without. shaking, half-maximum turbidities were obtained in less than 2 minutes of shaking. After 60 minutes of shaking, turbidity continued to increase gradually for 4 hours at about 10% per hour. Emulsion formation as a function of gas-oil concentration is shown in FIG. 7, in hitch the lower curve represents the data obtained using 33 mcg/ml of bloemulsi- fier and the upper curve the data obtained using 100 mcg/ml of bioemulsifier, both in filtered sea water, with varying amounts of gas-oil. Each mixture was reciprocally shaken for 60 minutes at 150 strokes per minute, and emulsion formation then measured. Emulsions were formed over the entire gas-oil concentration range studied, 0.5 to 10G mg per ml. Below 1.5 mg gas-oil per ml, turbidities were directly proportional to gas-oil concentration. Between 8 to 30 mg gas-oil per ml, turbidity increased about 5 Klett units per mg gas-oil. 8. 2. EFFECT OF pH AND SALT CONCENTRATION ON EMULSION FORMATION Acirtcbacter bioemulsifier-induced emulsification of gas-oil as a function of pH is son in FIG. 8. The data shown in FIG. 8 were based on reciprocally shaking (150 strokes per minute at 25 C. for 60 minutes) flasks which contained 33 mcg/ml of bioemulsifier and 6 mg/ml of Agha-Jari gas-oil in 7.5 ml of either (a) sea water [ closed circles]; (b) 10 mM NaCl [ open circles); (c) 100 mM citrate-phosphate buffer [ triangles ] ; cr (d) 50 mr Tris-NaOH buffer [squares]. The pH of sea water and 1U mM NaOH were adjusted by addition of HCl or NaOH. In sea water, near maximum emulsions were obtained from pH 5 to at least pup. 9. Above pre 9 precipitation of salts prevented accurate measurements of emulsion. In aqueous solutions containing Tris buffer, citrate-phosphate buffer, or diluted saline, a sharp maximum was obtained between pH 5-6. Above pH 7, activity was completely lost. In order better to understand the different results obtained in sea water and fresh water, the effect of salts on bioemulsifier-induced emulsification was measured at pH 7.0 and the data summarized in FIG. 9. The data shown in FIG. 9 was based on the emulsification of gas-oil with the Acinetobacter bioemulsifier in distilled water to which had been added varying concentrations of magnesium chloride (closed circles) or sodium chloride (open circles). Emulsification was measured after reciprocally shaking (150 strokes per minute) the flasks for 60 minutes at 25 C. Maximum activity was obtained with 5-40 mM magnesium sulfate or magnesium chloride. Half maximum activity was achieved with 1.5 mM magnesium ions (mug++). Calcium chloride (10 mM) and manyanesc chloride (10 mM) could be substituted for magnesium sulfate On the other hand, sodium chloride (10-500 mM) had little effect on emulsion formation, either in the presence or absence of magnesium ions Concanuentav the ability of Acinetobacter bioemulsifiers to emulsify hydrocarbons above pH 6' is de- pendent upon divalent cations and appears to be independent of sodium chloride concentration. Because of this property, these bioemulsifiers are capable of functioning in the presence of high concentrations of sodium chloride found in sea water or connate water. 8.3. STABILITY OF EMULSAN-INDUCED EMULSIONS Gas-oil emulsions formed in the presence of Acinetobacter bioemulsifier slowly separate into two phases when allowed to stand undisturbed; namely, a lower clear aqueous phase and a turbid upper phase containing concentrated oil droplets, bound bioemulsifier and water. As observed with a phase microscope, emulsion breakage (emulsification) was a result of "creaming" due to density differences between the two phases and was not accompanied by droplet coalescence or aggregation. The rate of phase separation was followed1Sy turbidity measurements in a Klett tube to determine the stability of the emulsion as a function of the ratio gas-oil/bioemulsifier, the results being summarized in FIG. 10. Emulsions were formed after 120 minutes at 25 C. by reciprocally shaking varying concentrations of gas-oil with either 33 mcgXial (FIG. LPA) or 100 mcg/ml (FIG. 108) of Acinetobacter bioemuisifier, and then allowed to stand without shaking from zero time (i.e., immediately after formation of the emulsion) until 120 minutes. In FIGS. 10A and 10B, percent Klett units (Klett units at t=x divided by Klett units at t=0, expressed as percentage) are plotted against stanainy time. The numbers on each curve refer to the weight ratios ot gas-oil/bioemulsifier. As shown in FIGS. 10A and 108, emulsion stability depended more upon the ratio of gas-oil/bioemulsifier tnuiz on the absolute concentration of bioemulsifier or gas-oil used to form the emulsion. With gas-oil/bioer.ulsifier ratios of less than 25, over 24 hours standing was required for a 50% decrease in turbidity. With ratios between 25-200 and 200-1000, half-maximum turbidities were reached in 1-24 hours and 10-60 minutes, respectively. In all cases, the upper "cream" immediately dispersed in aqueous media. Emulsion breakage was enhanced by divalent cations. Rate of flotation of oil droplets as a function of gas-oil/bioemulsifier ratio is shown in FIG. 11, in which the upper curve represents data obtained using 100 -mcg/ml of bioemulslfier and the lower curve represents data obtained using 33 mcg/ml of bioemulsifier, both with different gas-oil concentrations. The average radii of the droplets, r, were calculated from Stokes equation 2 V = 21800 r , where V is the velocity at which oil droplets rise in cm/sec and r is the radius in cm, using 0.90 g cm 3 ; as the density of gas-oil. The calculated droplet sizes were In good agreement with measurement of droplet size by phase microscopy (using calibrated eye-piece micrometer). With a ratio of gas-oil/bioemulsifier of 50, the droplets were barely visible by light microscopy. 8.4. LOWERING OF OIL/WATER INTERFACIAL TENSIONS The ability of Acinetobacter bioemulsifiers to lower the interfacial tensions between a series of n-alkanes and sea water is shown In FIG. 12, whicr i,iustrates the inter facial tensions of n-alkan-es from 6 to 16 carbon atoms in sea water containing 0.18 bioemulsifier. Values for interfacial tension were determined at 27 C. using the spinning drop interfacial 'ensIoreter. Using similar tecnnicues, the interfacial tensions between Prudhoe Bay crude oil and sea water were measured using 1 and 10 mg of bioemulsifier per ml, yielding 8.3 and 6.9 dynes per cm, respectively. 9. SPECIFICITY OF THE HYDROCARBON SUBSTRATE Apart from classification as anionic, cationic or nonionic, most emulsifiers are described in terms of their HLB numbers, which is a measure of the hydrophile-lpophile balance of the emulsifier. Very often, emulsifiers with similar HLB numbers interact differently with hydrocarbon substrates. Because biologically produced polymers often exhibit specificities not found in chemically synthesized materials, the hydrocarbon substrate specificity for Acinetobacter bioemulsifier-induc,ed emulsion formation was studied using a wide variety of pure -hydrocarbons, binary mixtures of hydrocarbons, crude oils, fractions of crude oils and mixtures of crude oil fractions and pure hydrocarbons. 9.1. EMULSIFICATION OF PETROLEUM FRACTIONS The ability of a-emulsans and e-emulsans to emulsify crude oil and fractions of crude oil is summarized below in Table XIV. All crude oils tested were emulsified by both types of Acinetobacter bioemulsifiers. In addition to the crude oils shown in Table XIV, various crude oils from Alaska, Louisiana and Texas were emulsified by both Acinetobacter bioemulsifiers. Gas-oil was a better substrate for Acinetobacter bioemulsifier-inuuced emulsification than kerosene or aoli, both of which ford somewhat unstable emulsions. In general, better emulsions were formed with a-emulsan than it S-emulsan and, in some instances; could only be formed with a-emulsan 9.2. EMULSIFICATION OF PURE HYDROCARBONS Straight and branch chain aliphatic hydrocarbons from heptane to octadecane were emulsified only to a slight extent by the Acinetobacter bioemulsifier as illustrated by the data in FIG. 13 which is a graphical representation showing the relationship of the amount of emulsification of various straight and branch chain alkanes as a function of carbon number. The data summarized in FIG. 13 was obtained using 100 mc/ml of Acinetobacter bioemulsifier and 0.05 ml hydrocarbon, the open circles referring to straight chain alkanes while the closed circles refer to 2,2,5-trimethylhexane, 2-methyldecane, 2,6-dimethyldecane and 2,6-dimethylunidecane. Increasing or decreasing the hydrocarbon concentration by a factor of five did not improve emulsification. Pentane and hexane were also not emulsified effectively; however, quantitative data for these two paraffins were not obtained because of extensive evaporation during incubation. The solid hydrocarbons, nondecane, n-octacosane and hexatriacontane, were not dispersed by Acinetobacter bioemulsifier. Emulsification of n-alkyl cyclohexane derivatives ranging from propylcyclohexane to tridecylcyclohexane by Acinetobacter bioemulsifier are summarized in FIG. 14, which graphically illustrates emulsification ol various alkylcyclohexanes as a function of carbon number. The data shown in FIG. 14 was obtained using 0.2 ml hydrocarbon and either 25 mcg/ml (closed circles) or 100 w;cg/ml (open circles) of Acinetobacter bioemulsifier. As shown in FIG. 14, two peaks of activity were Observed, corresponding to octylcyclohexane and decylcyclohexane. The data for octyl, nonyl and decs-lcyclo- hexanes were obtained from redistilled materials which contained no ultraviolet-absorbing impurities. Concentrations of octyl and decylcyclohexane as lo as 5 mg per ml were rapidly and completely emulsified by 50 mcg/ml of bioemulsifier Nonylcyclohexane did not contain any apparent inhibitors of emulsification, since mixtures of octyl and nonylcyclohexane were emulsified to about the same extent as octylcyclohexane alone. Bicyclohexane and decal in were not emulsified significantly Emulsification of n-alkylbenzene derivatives by Acinetobacter bioemulsifier are summarized in FIG. 15, the data for which was obtained using 0.01 ml hydrocarbon and 50 mcg/ml of bioemulsifier. Maximum activity was obtained with hexyl and heptylbenzenes. The total number of carbon atoms in the side chains may be more crucial than the chain length since p-diisopropylbenzene behaved like hexylbenzene. The low molecular weight benzene deriva tives, toluene, p-xylene, m-xylene, ethy ] -benzene and 1,2,3, 4-tetramethylbenzene, were not emulsified sig- nificantly. Aromatic compounds containing more than one ring, naphthalene, biphenyl, phenanthrene, anthracene, 3-phenjw toluene, 1-methylnaphthalene and 2 ethylnaph- thalene were also not emulsified significantly by the Acinetobacter bioemulsifier. 9.3. EMULSIFICATION OF MIXTURES OF PURE HYDROCARSONS Table IX summarizes a number of experiments in which the Acinetobacter bioemulsifier-induced emulsificarion of aliphatic, aromatic and cyclic hydrocarbons were measured in the presence of hexadecane or 1-methylnaphthalene. AlthC'cjh neither the aliphatic compounds nor 1-methylnaphthalene were emulsified by themselves, all mixtures containing the aromatic compound and one of the aliphatic hydrocarbons were excellent substrates for emulsification by the bioemulsifier. The ability of aromatic compounds to stimulate emulsification of aliphatics was not limited to 1-methylnaphthalene, but occurred with toluene, p-xylene, 3-phenyltoluene and 2-met'hylnaphthalene. Addition of hexadecane to the aliphatic compounds did not stimulate emulsification, that is, only an additive effect was observed. The minor exception to this finding was nonadecane which became liquid when mixed with hexadecane. ;As mentioned above, the only aromatic compounds that served as substrates for emulsification by Acinetobacter bioemulsifier were alkylbenzene derivatives containing six or seven carbon atoms on the side chain(s). Aromatic compounds containing less than six carbon atoms on the side chain were converted into good substrates for emulsification by addition of hexadecane. Hexylbenzene and diiopropylbenzene were converted into even better substrates for emulsification by addition of hexadecane. On the other hand, heptyl, decyl and pentadecylbenzene were emulsified more poorly in the presence of hexadecane than by themselves. Only alkylbenzene derivatives containing side chains of five or more carbon atoms were activated by 1-methylnaphthalene. 1,2,3,4-Tetramethylbenzene was poorly emulsified by the bioemulsifier even in the presence of hexadecane or 1-methylnaphthalene. With few exceptions, cycloparaffin derivatives were converted into better substrates for Acinetobacter bioemulsifer-mediated emulsification by addition of either hexadecane or 1-methylnaph- thalene. In general, cyclohexane ueLiv ves wiLh short side chains (e.g., ethylcyclohexane) were agitated more efficiently with aliphatic than aromatic compounds, while derivatives with long side chains (e.q.. duodecylcyclohexane) formed better emulsions in the presence of 1-methylnaphthalene than hexadecane. Dicyclohexane behaved like an aromatic compound in that it was emulsified by the bioemulsifier in the presence of hexadecane but not 1-methylnaphthalene. The fused dicylic compound decal in could not be emulsified by the bioemulsifier even by addition of hexadecane or 1-methylnapilthalene. Acinetobacter bioemulsifier-induced emulsion formation as a function of the relative concentrations of aliphatic (hexadecane) and aromatic (methylnaphthalene) compounds is shown in FIG. 16, the data for which was obtained using 50 mcg/ml of bioemulsifier and 0.05 il of various mixtures of hexadecane and l-methylnaphthalene (closed circles) or hexadecane and 2-methylnaphthalene (open circles). Using either 1-methylnaphthalene or 2-methylnaphthalenet maximum emulsion was obtained with 25 vol. % hexadecane. Over fifty percent maximum emulsion was obtained with ratios of hexadecane/methylnaphthalene from 4:1 to 1:6. An identical experiment using decane in place of hexadecane yielded similar curves except that the peak of emulsion activity was obtained with 33 vol. % decane. TABLE IX Emulsification of Mixtures of Aliphatic, Aromatic and Cyclic Hydrocarbons by Acinetobacter Bioemulsifier Hydrocarbona Emulsion (Klett units) no plus plus 1 addition hexa- methylnaphdecane decane thalene Aliphatics decane 15 41 185 tetradecane- 13 50 216 hexadecane 20 31 284 nonadecane 0 (solid) 79 285 2,2,5-trimethylhexane 0 34 89 2,2-dimethylunadecane 0 2 105 Aromatic biphenyl 0 (solid) 123b 19b naphthalene 0 (solid) 96b 26b phenanthrene 0 (solid) 61b 36b toluene 22 3-phenyltoluene 0 157 0 1-methylnaphthalene 0 284 0 2-methyinaphtha)ene 0 244 0 p-xylene 22 75 15 ethylbenzene 9 117 21 propylbenzene 9 90 23 pentylbenzene 4 197 85 hexylbenzene 98 188 165 p-diisopropylbenzene 96 299 192 heptylbenzene '105 82 186 decylbenzene 38 <RTI ID=70.5> 31' 49 TABLE IX (cont'd) Hydrocarbona Emulsion (Klett units) no plus plus 1 addition hexa- methylnaph decane ¯¯¯¯¯¯¯¯¯ decane thalene pentadecylbenzene 21 0 5 1,2,3,4-tetramethylbenzene 28 35 9 Cycloparaffins ethylcyclohexane 8 81 43 propyl cyclohexane 3 81 64 butycyclohexane 0 111 57 hexylcyclohexane 5 9 116 heptylcyclohexane 1 32 131 octylcyclohexane 109 151 175 nonylcyclohexane 0 0 249 decylcyclohexane 79 192 171 duodecylcyclohexane 5 0 72 decalin 0 15 17 dicyclohexane 14 201 39 a/Experiments were performed using 50 mcg/ml of 6-emulsan and 0.025 ml of each hydrocarbon (20 mg for solids). For solubility reasons, 0.05 ml solutions containing 10% biphenyl, 10% naphthalene and 5% phenanthrene in hexadecane or 1-methylnaphthalene were used. 9.4. EFFECT OF ADDITION OF ALIPHATIC AND AROMATIC COMPOUNL)S ON EMULSIFICATION OF PETROLEUM FRACTIONS The results shown in Table IX and summarized in FIG. 16 lead to the conclusion that the ability of the Acinetobacter bioemulstfiers to emulsify hydrocarbons depends on the relative concentrations of aliphatic, cyclic and aromatic components in the hydrocarbon substrate. To verify this conclusion, experiments were designed to determine whether or not addition of hexadecane or methylnaphthalene could enhance Acinetobacter bioemulsifier-induced emulsification of petroleum fractions which had been fractionated to separate a fraction rich in aliphatics (Fraction 1) from two fractions (Fractions 2 and 3) rich in aromatics. These experiments, which are more fully described below in Section 13.13, show that the ability of a-emulsan to emulsify both kerosene and gasoline was enhanced greatly by 2-methylnaphthalene but not by hexadecane. Addition of even one part of the aromatic compound to ten aris of gasoline or kerosene resulted in a much improved substrate for emulsification. The requirement for both aliphatic and aromatic constituents was further supported by studying emulsifinat;on of co3iimn fractionated crude oil. Although crude oil itself is emulsified by the Acinetobacter bioemulsifier, none of the fractions were good substrates by themselves. However, mixtures contain ing one fraction (Fraction 1) rich i!-l aliphatics and the other (Fractions 2 or 3) rich in aromatics were efficiently emulsified. 10. SUMMARY OF DIFFERENCES BETWEEN a-EMULSANS AND -EtiULSANS The major differences between a-emulsans and emulsans, the two classes of bioemulsifiers produced by Acinetobacter Sp. ATCC 31012, may be subdivided into (a) differences in yield; (b) differences in structure; and (c) differences in emulsifying activity. Table X sum- marizes several of such differences between &alpha;-emulsans, B-emulsans and their respective deproteinized derivatives. Although the particular a-emulsans referred to in Table X were prepareby growing Acinetobacter Sp. ATCC 31012 on ethanol medium, while the B -emulsans were prepared from an identical fermentation medium using identical growth conditions except that hexadecane was substituted for ethanol, substantially identical results are obtained when the a-emulsan is prepared by growing the organism on sodium palmitate instead of ethanol. Both bioemulsifiers (&alpha;-emulsan and ;-emulsan) were purified by ammonium sulfate fractionation, and the deproteinized derivative of each bioemulsifier was prepared by hot phenol extraction and further purified prior to analysis. Total fatty acids content was determined using the hydroxamic acid test, taking the average equivalent weight of the fatty acid esters to be 230 TABLE X Differences Between &alpha;-Emilsans and ss-Emulsans and Their Respective Deproteinized Derivatives Bioemulsifiera Yield Specific %Estersb A/B Ratioc (mg/ml) Activity (units/mg) &alpha;-Emulsans 1-5 200-350 --- -- Apo-a-emulsans --- 100-200 8-14 0.2-0.5 ss-Emulsans 0.1-0.75 50 Apo-ss-emulsans --- 25-75 2-3 > 0.8 a/ a-Emulsan was prepared from an ethanol medium and ss -emulsan from a hexadecane medium. Both bioemulsifiers were purified by ammonium sulfate fractionation. The deprcteinized derivatives of each bioemulsifier were pr±- pared by hot phenol extraction and further purified prior to analysis. Total fatty ester content was determined using hydroxamic acid test, taking the average equivalent weight of the fatty acid esters to be 230. c/ A and B refer to 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid, respectively. 10.1. DIFFERENCES IN YIELD As shown by Table X and as further illustrated in the data summarized in FIGS. 2 and 3, the yield of a-emulsan is invariably greater tan the yield of ss-emulsan even when identical cultures of Acinetobacter Sp. ATCC 31012 are used as innocula on ethanol and hexadecane media, respec- tively. Moreover, when the organism is grown on other carbon sources which produce a-emulsans, such as palmitic acid and dodecane, the yields of the high-ester a-emulsan are higher than the ss-emulsans obtained when the organism is grown on such carbon sources as pentadecane or hexadecane. 10.2. DIFFERENCES IN STRUCTURE Purified a-emulsans have a higher specific activity than purified S-emulsans, which is probably due to the higher fatty acid ester content of a-emulsans and may also be due to the generally higher amount of 3-hydroxydodecanoic acid in a-emulsans compared to ss-emulsans. As shown in Table X, the apo-a-emulsan cor- ponent of the a-emulsan contained from 8 to 14% by weight of total esters, while the apo-ss-emulsan component of the S-emulsall contained appreclably less (2-3%) fatty acid esters Moreover, the apo-a-emuls n content of a-emulsans general 1" possess a lower ratio of 2-hydroxydodecanoic acid to 3-hydroxydodecanoic acid (usually about 1:4 to about 1:2) than in the apo-ss-emulsan component of -emul- sans. Table XI summarizes the different ester compositions of an apo-a-emulsan derived from deproteinization of an a-emulsan formed when Acinetobacter Sp. ATCC 31012 was grown on an ethanol medium when compared to the apo-ss- emulsan derived from a ss-emulsan formed when the organism was grown on hexadecane. Each of the deproteinized Acinetobacter bioemulsifiers was hydrolyzed in KOH/methanol for 4 days at room temperature, the corresponding mixture of methyl esters were formed with diazomethane and the methyl esters of each mixture were then fractionated by chromat-ography . TABLE XI Ester Composition of Apo-&alpha;-emulsan and Apo-ss-emulsan Fatty Acid Apo-a-emulsan Apo-ss-emulsan (% (% Wgt) (% t) Decanoic 0.84 0.39 Dodecanoic 1.70 0.41 Dodecenoic 0.18 0.08 2-Hydroxydodecanoic 0.78 0.44 3-Hydroxydodecanoic 2.92 0.54 Hexadecanoic 0.05 trace Hexadecenoic trace trace Octadecanoic 0.02 trace Octadecenoic trace trace Unidentified 0.89 0.53 TOTAL ESTERS 7.4 The data shown in Table XI confirm the general rule that in the apo-a-emulsan content of u-emulsans, the aggregate amount of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid is usually about 508 of the total fatty acid esters and may be as high as 70% of the fatty acid esters in the lipopolysaccharide. The same general rule also applies to a-emulsans prepared by growing Acinetobacter Sp. ATCC 31012 on one or more fatty acid salts as the primary assimilable carbon source. 10.3. DIFFERENCES IN SMULSIFYING ACTIVITY The data contained in Table XIV below show that although a-emulsan and R-emulsan are both excellent emulsifiers for crude oils and are both only fair emulsifiers for kerosenes, a-emulsan is much more effective than ss-emulsan in the emulsification of gas-oils. Moreover, Bunker C fuel oil is emulsified by a-emulsan but not by ss-emulsan. In general, experience has shown that a-emulsans give better emulsions than $-emulsan with hydrocarbon substrates which contain both aliphatic and aromatic (or other cyclic) components. 11. SORPTIVE PROPERTIES OF EMULSANS AND THEIR DERIVATIVES ON SOLID SUBSTRATES The adsorption or non-adsorption of emulsans and apoemulsans on various types of solid substrates, such as sand, limestone or clay minerals, were measllreà to determine whether these anionic lipopolysacchari '5 could function as thioemulsifiers in the presence of such sulid substrates. 11. 1. NON-ADSORPTION ON SALAD AND LIESO Neither emulsans nor apoemulsans are adsorbed to any significant extent on sand or on limestone over the pH range in which these bioemulsifiers will be used to form oil-in-water emulsions. When oil is present on the sand or limestone, such as in sand or sandstone reservoir formations or in limestone reservoir formations, the oil may be recovered by enhanced oil recovery using chemical flooding with dilute concentrations of emulsan, since bench scale experiments have shown that when oil-saturated sand or oil-saturated limestone are treated with dilute solutions (i.e., from 0.1 to 0.5 mg/ml) of cL-emulsan containing magnesium ions (10 mM), over 90% of the oil can be removed from the oil-saturated sand and over 98% of the oil can be removed from the oil-saturated limestone. Com- parable results may be obtained using sea water solutions of emulsans, since the presence of sodium chloride in the concentrations found in sea water or in connate water do not affect the ability of emulsans to emulsify crude oils, including crude oils which are quite viscous or tarry, which are found in sand (or sandstone) formations or in limestone formations-or which remain in such formations after secondary recovery techniques (such as steam stripping) are employed. 11.2. ADSORPTION ON ALUMINOSILICATE CLAYS Emulsans and their deproteinized derivatives, the apoemulsans, both of which are strongly anionic, are adsorbed on aluminosilicate ion-exchangers, such as kaolin bentonite and other clay minerals which have ion-exchange capacity. The Frets of adsorption of a-emulsan on bentonite are shown in FIG. 17, which summarizes the rate of adsorption of a-emulsan onto 0.5 g bentonite in a 20 ml solution of 20 mM Tris-Mg buffer I20 m tris (hydroxymethyl)aminomethane hydrochiride and 10 m magnesium sulfate] containing 100 mcg/ml of emulsan. The mixture was shaken at 20 C. at 110 strokes per minute in 100 ml flasks, with samples being removed every 10 minutes for assay of a-emulsan not bound to the bentonite. Under these conditions, over 958 of the a-emulsan was adsorbed and equilibrium reached in 40 minutes. The amount of a-emulsan adsorbed by the aluminosilicate clay was a function of the amount of clay, about 70% of the a-emulsan being adsorbed at a bentonite7emulsan ratio of 100:1 and over 955 of the a-emulsan at ratios over 400:1. 11.3. FLOCCULATION OF CLAYS Adsorption of emulsans (as well as the apoemulsans, #-emulsans and proemulsans) onto suspended particles of aluminosilicate clays, such as kaolin and bentonite, results in rapid flocculation of such particles. By way of illustration, mixing 1 g of bentonite with 20 ml water containing only 100 mcg/ml of ccemulsan causes the bentonite to sediment from five to ten times faster than in the aense of emulsan. Moreover, the supernatant fluid obtair,d using emulsan-mediated flocculation was clear, while the sedimentation of bentonite without the emulsan yielded an upper layer which remained opalescent even after prolonged standing. Similar results may be obtained with other clay minerals with ion-exchange capacity. .he floWcuiating properties of elnuisans (which apply equally to the corresponding apoemulsans as well as to their deacylated derivatives, t-emulsans and proemulsans, all of which are also anionic) prevent the packing of aluminosilicate clays into a dense precipitate in such manner that the volume occupied by the flocculated clays is several times greater (three times in the case of bentonite) than in the absense of the lipopvlysaccr.aride. The flocculated aluminosilicate clays now have certain fluid and flow properties which suggest an enormous number of uses for emulsans and apoemulsans and their derivatives in flocculation, including (a) the use of emulsans and apoemulsans as a clay particle flocculent in drilling muds; (b) the, prevention of clogging in sewage treatment systems; (c) enhancing the porosity of clay solids to structure poor soils for uses in agriculture; (d) the inclusion of emulsans in coatings and aerosol sprays containing such clays; and (e) the use of emulsans and apoemulsans as a general flocculating agent for recovery and settling, processes. 11.4. RELATIONSHIP OF FLOCCULATION TO BREAKING OIL/WATER EMULSIONS Adsorption of emulsans onto aluminosilicate clays creates an oleophilic clay which, in turn, is capable of breaking a stable oil/water emulsion formed with the bioemulsifier. By way of illustration, emulsification of 1 ml ka Jari crude oil in 10 ml sea water containing about 1 mg/ml of bemulsan forms an oil-in-water emulsion which is stable after standing two days. The addition of 1 g of preswelled bentonite to this stable emulsion, followed by intense shaking for about 20 seconds, resulted in breakage of the emulsion in 15 minutes. After 20 hours, there were two separated layers, namely an upper clear liquid and a lower "el-like sediment which occupied about one-half of the prior volume of the emulsion. These sorptive properties of emulsans and apo enulsans with respect to aluminosilicate clay n-excha,G ,s may also be utilized to remove oil and hydrocarbonaceous sludge from oily ballast water or other oily water, either by filtering such oily waters through an aluminosilicate clay (such as kaolin or bentonite) on which an emulsan or apoemlusan had been adsorbed or, alternatively, by adding the emulsan or apoemulsan to the oily water and then filtering the mixture through an aluminosilicate clay. In both cases, the filtrate will be clear and the oily residue will remain in the clay filter. 12. ENVIRONMENTAL AND E:NERGY-REL7sTi USES The extracellular microbial polysaccharides produced or derived from Acinetobacter Sp. ATCC 31012, which include both the enfulsans and apoemulsans and their respective salts, are among the most efficient oil-in-water emulsifier ever discovered and possess a high degree of specificity in both fresh water and sea water for emulsifying those hydrocarbon substrates which contain both aliphatic and aromatic or other cyclic components (wherein two different components may be present in the same compound or in different compounds), properties which make these unique bioemulsifiers (particularly the a-emulsans) ideal for many envirommental ana energy-related uses, including cleaning oil-contaminated vessels, oil-spill management and enhanced oil recovery by chemical flooding. 12.1. CLEANING OIL-CONTAMINATED VESSELS 12.1. í. -COPE OF THE PROBLE:I During this century the demand for petroleum as source of energy and as a xDrimarev raw material for the petrochemical industry has resulted in an increase in world production from 29 to over 2,400 million metric tons per year. This dramatic increase in the production, refining and distribution of crude oil has also brought with it an ever-inereasing problem of environmental pollution, which has been a consequence of the massive movements of petroleum by oil tankers from the areas of high produce tion to those of high consumption. It has been estimated that 0.5% (12 million metric tons per year) of transported crude oil finds its way into sea water, largely through accidental spills and deliberate discharge of ballast and wash waters from oil tankers. The toxicity of crude and refined oil to marine ecology and even more directly to man is well documented [ D. F. Boefsch et al., "Oil Spills and the Marine Envircnment", Ballinger Publ., Cambridge, 1974, 114 pp.; A. Nelson-Smith in the collected papers edited by P. Hepple, "Water Pollution by Oil", Elsevier, New York, 1971, pp. 273-80] and need not be discussed in detail. Suffice it to state that crude oil contains mutagenic, carcinogenic and growth-inhibiting chemicals and that even small quantities (5-100 mcg per liter) of certain petroleum fractions destroy microalgac and juvenile forms of micro organism. Furthermore, it has recently been reported [ I. Chett et al.,.Nature, 261, 308-9 (1976) ] that petroleum inhibits microbial decomposition of organic matter in sea water by interfering with chemotaxis. To put it simply, oil pollution in the ocean in general and in the coastal waters in particular presents a serious Fobl to coitnercial fisheries, recreational resources, and public health. 12.1.2. OIL TANKERS AND POLLUTION Substantially all crude oil is transported k & y very large tankers (VLT), which ships are usually divided into 12 or more large cargo compartments, each with about 20,000- ton capacity. These compartments are interconnected via large pipes to two smaller compartments about 2,000 tons each, referred to as "slop" tanks. These slop tanks are designed to serve as oil-water separators. After the cargo compartments are filled with crude oil, the VLT begins its voyage. Upon arrival, the cargo is discharged Into. large on-land oil storage tanks, during which operation about 99.58 of the crude oil is pumped out in about 24 hours. The residual oil remains stuck to the sides, platforms, ribs, and pipes of the compartment. As the oil is discharged, the ship rises out of the water. Before putting to sea, the VLT must take aboard large quantities of ballast water. During the return voyage to the oil-producing country, this ballast water mixes with the residual (approximately 1,000 tons In a 250,000-ton VLT) oil. Disposal of this heavily con taminated, oily ballast water is the major contributor to chronic sea pollution. In addition, cargo compartments ot oil tankers must be cleaned periodically to prevent clogging and sludge accumulation that otherwise would reduce te ship's cargo capacity, as well as inhibit dis- charge @ crude oil. Moreover, if the oil tanker Is a multipurpose vessel, taking on grain or ore irnmediately after discharging its oil cargo, tie cargo compartmente must be clcdnd after every voyage. Presently, cargo compartments of oil tankers are usually cleaned with high-pressure jets of sea water; the combined ballast and wash waters are then either (a) discharged at sea, (b) transferred to separator tanks on shore where harbor facilities permit, or (c) transferred to t'ie slop tanks in which te bulk water has bottom is discharged, <RTI ID=83.51> additional oily ballast water is added, and the process is repeated until the ship takes on fresh oil that is then loaded on top of thc residual oil (load-on-top technique). one of these techniques is totally satisfactory either from the ecological or operational point of view. Direct discharge at sea is still the major means of disposing of oily water. It will remain so until pollution laws are made stricter and more enforceable or other techniques prove more economical. Direct discharqe at se requires no special equipment and, most important of all, can be carried out during the ballast voyage so that no loss of time is incurred. The 1954 international Agreement for the Prevention of Pollution at Sea, as amended in 1962 and in 1969, is the only international agreement regarding pollution by ships that is currently in force. This Agreement allows for unlimited discharge of oil outside of specified prohibited zones. Within tIe prohibited zones, discharge is restricted to a rate no greater than 1 ton of oil in 10,000 tons of water, without regard to total quantity. These regulations do not apply, however, if the tanker's cargo compartments have been cleaned and the subsequent discharged ballast water does not produce visible traces of oil on the tauter surface. The 1973 Marine Pollution Convention Agreement, when ratified and if enforced, should decrease oil pollu- tion by a factor of about ten by forcing VLTs to use tiic load-on-top technique. The most serious disadvantage t the unrestricted use of this oil-water separator system i- that the most toxic components of petroleum are discharged into the sea, often near shore. I-t is only a matter of time, therefore, before there is an internatione) agreement prohibiting all intentional discharge of oil from sh into the ocean. 12.1.3. ECONOMIC CONSIDERATIONS To eliminate the oily ballast dice, many tankers have been required to be retrofitted and new tankers are being constructed with sufficient clean ballast space so that water does not have to be taken into the oil cargo compartments, which effectively reduces a tankers carrying capacity by 2U to 30%. Discharge of ballast water for treatment at the terminal ports is required by certain countries, but ttiis alternative : a created more problems than it has solved. Studies have shown that cleaning the tanker during the ballast voyage with recovery of the oil for fuel or, alternatively, cleaning the ship at special cleaning stations with recovery of the oil for fuel value or for refining are economically justified if the cleaning process can be designed to be efficient, rapid and not later intensive or dangerous. Unfortunately, no existing cleaning process meets all such criteri. Present methods for cleaning cargo conpartments, which are employed before an oil tanker can enter drydock for repairs since all cargo compartments must be cleaned and rendered gas free, are tine consuming, dangerous and expose the worker to serious health hazards. High-pressure jets of water striking the sides of a tank containing explosive mixtures of gases have caused major explosions on oil tankers. Those regions of the tank protected by obstructions from direct exposur to t water get must be cleaned by hand. Furthermore, it a hea,vy buildup of sludhe has taken piace, which is more often the cause than not as more and more transported crude oil contains a higher proportion of so-called residual" oils, mechanical washing is frequently not effective. An alternative approach to cleaning out Oil tank± is the use of hydrocarbon-degrading microorganisms. The feasibility of such an approach was demonstrated by us in a controlled experiment aboard an oil tanker during its ballast voyage (E. Rosenberg et al. in the collected papers edited by A. W. Bourquin et al., "Impact on the Use of Microorganisms on the Aquatic Environment", EPA Neport 660-3-001, 1S75, pp. 157-68 ] . In that experiment, removal of the sludge fron; the cargo compartment was nor possible by providing conditions that favored bioemulsifica tion rather than optimum cell growth. Subsequent work, which forms the basic for the present ihvention, led us to conclude that cleaning hydrocarbonaceous residues from. tankers, as well as other oil-contaminated vessels used to transport or store crude oil or petroleum fractions, required the use of bioemulsifiers which could efficiently, rapidly and safely emulsify the oily residue so that it could be removed from the vessel and, if desired, recovered for fuel value or refining. 12.1.4. UTILIZATION OF a-EMULSANS IN CLEANING OIL-CONTAMINAT±D VESSELS Cleaning hydrocarbonaceous residues (Including residual crude oil) from oil-contaminated vessels in accordance with the process of the. invention requires (a) washing the oil-contaminated surfaces of such vessels with an aqueous solution, e.g. in sea water or fresh water, containing at least 10 mcg/ml, preferably from 10mcg/ml to 100mg/ml, e.g. from 10mcg/ml to 20 mg/ml, of &alpha;-emulsans and about: 5mM or higher or a divalent cation, such as magnesium, calcium or manganese, to from an oil-in water emulsion of such hydrocarbonacous residues; acid (b) removing such oil-in-water emulsion from the cleaned vessel. The amount of a-emulsan in the wash water can be predetermined, based on the composition of the particular hydrocarbon residue to be removed. Usually, complete cleaning can be accomplished with hydrocarbon/emulsan weight ratios of about 1000:1 to 10000:1, the higher the ratio the less stable the emulsion. The cleaning solution can be prepared directly from the fermentation broth or, alternatively, from a relatively concentrated solution of a-emulsans (10 mg/ml or higher) by appropriate dilution with sea water or tap water such that the final solution contains ahout 5 ; or more of the divalent cation without which the a-emulsans are ineffective as bioemulsifiers. These divalent cations are normally present in sea water and in "hard" waters. The cleaning solution may appear cloudy below ph 7, but this cloudiness can be eliminated by adding a small amount of ammonium to the a-emulsan solution. Although the washing operation may be conducted with only gentle agitation, best results are obtained using eQuipment, such as jet nozzles, which vigorously agitate the wash solution and cause the oil-in-water emulsion to form more rapidly. Any suitable jet nozzles may be ut d, the most efficient of which are the portable jet spray nozzles manufactured by Butterworth Systems, Inc., Florham Park, New Jersey, for cleaning storage tanks, tank cars and trucks. This type of equipment may also be used inboard tankers which do not have Butterworth or comparable jet spray systems built into the cargo com,partments. After reoal of the wash solution fro the vessel, the resultant oil-in-water emulsions can be broken by physical or chemical techniques, and the oil recovered for fuel value or for refining. Selection of suit-able oil-water separators for this purpose may be made fro the standard equipment widely used throughout the oil industry, the choice of such equipment being governed by cost effectiveness for a particular application. 12.2. OIL SPILL MANAGEMENT Oil spill management is another environmentally iitportant use for the emulsifying agents of the invention. In most processes for cleaning oil spills, an aqueous solution of a detergent or surfactant is oulit into contact with the oil slick, which is floating on the sea or which has been washed ashore or deposited on land to emulsify the oil so that it may be dispersed and either removed or biodegraded. Most of the detergents or surfactants commonly used are somewhat toxic to marine life and are not biodegradable. By using the emulsifying agents produced by the process of the invention, namely the aqueous solution e.g.rnsea water or fresh water containing e.g. from about 10 mcg/ffl to about 20 mg/ml of a-emulsans and an effective concentration of at least one divalent cation, not only is it possible to emulsify the oil witlJ less emulsifier which is itself biodegradable but also to avoid toxolo-ral problems since emulsans are non-toxic in the concentratIons in which they are used as bioemulsifiers. This technique is especially useful in cleaning beaches conta:".-inated with oil. 12.3. ENHANCED OIL MCOV±R-Y Enhanced oil recovery by chemical flooding represents a particularly important energy-relatecs use for emulsans. All processes in the en)ancec' recovery of oil by chemical floodIng involve thc injection of a chemically-augmented "slug" comprising water and one or more added chemicals into a petroleum reservoir followed by displacement of the "slug" through the reservoir to recover crude oil from the injected reservoir. Because of the unique combination of properties of emulsans and particularly for a-emulsans -namely (a) that emulsans on a weight-for-weight basis are probably the most efficient oil-in-water emulsifiers discovered; (b) that emulsans exhibit a high degree of specificity in emulsifying hydrocarbon substrates that contain aliphatic and aromatic or other cyclic fractions, which are present in all crude oils including the viscous and tarry crudes remaining-in the reservoir after primary and secondary recovery; (c) that emulsans function effectively even in the presence of high concentrations of salts, such as brine; and (d) that emulsans are not adsorbed to any significant extent by sand or sandstone or limestone -- using a chemically-augmented slug which contains effective concentrations of emulsans and the necessary divalent cation will appreciably increase the recovery of oil from sand or sandstone or limestone formations. Moreover, these anionic lipopoly saccharides may be used as the sole emulsifier or in conjunction with other emulsifying agents (such ac the nonionic surfactants used for tertiary oil recovery), as well as in conjunction with the mobility control polymers used in such processes. 13. EXAMPLES The following examples are illustrative o the re- paration, purification and some of the uses of the &alpha;-emulsans and apo-&alpha;-emulsans aerived from Acinetobacter . ATCC 3101 when the compared to the ss-emulsans end apo-emulsans which, in turn, are derived from growing the same organism on a differen-t substrate 13.1. PREPARATION OF &alpha;-EMULSAN FROM ETHANOL IN FRESH WATER MEDIA To a 60-liter fermenter fitted with tour baffles and a variable-speed agitator were added 733.6 g of dibasic potassium phosphate [K2HPO4.3H2O], 240 s of monobasic potassium phosphate, 8 g of magnesium sulfate [MaSO4.7H2O], 160 g of ammonium sulfate and a sufficient amount of deionized water to make 40 liters. The medium was sterilized for 40 minutes at 121 C., after which 800 ml of absolute ethanol (2* by volume) was added. The final pli of the medium was G.X. Growth was initiated with 2 niters (5%) of a late exponential culture of Acinetobacter Sp. ATCC 31012 grown under similar fermentation conditions. The fermentation was conducted at 30 C., with aeration maintained at 15 liters of air per minute and agitation at 250 rpni. The pH of the fermentc- tion broth was maintained between pH 6.2 and 6.7 by the dropwise addition of concentrated ammonium hydroxide, which required approximately 185 ml of concentrated ammonium. hydroxide during the first 30 hours. Throughout the fermentation, foam was cor,trollcd by automatic pulse additions of 2 silicone defoaner (Dow Cording 525, sterlizable, diluted 1:8), in connection ith which an aggregate of 50 ml was added during the first 30 hours. Commencing at the 11th hour of fermentation, ethanol was continuously added to the termentation broth at the rate of 40 ml per hour. Arninonium sulfate was periodically added to the fermentation broth at the rate of 2 g per hour for the first 30 hours. Maximum groth was obtained between 24 to 30 hours after inoculation. The yield of a-emulsan was 4 9 per liter, with a cpll mass of approximately b a (dry weight basis) per liter. Analysis of the crude emulsan, which was performed on the crude extracellular fluid following extensive dialysis against water, showed that it contained a total ester content of 10% using the hydroxamic acid test and assuming that the average molecular weight of the fatty acid esters was 230. Using substantially identical conditions, as much as 5.3 g per liter of a-emulsan were obtained with a cell mass of about 9 a (dry weight basis) per liter. 13.2. PREPARATIOIQ OF a-EMULSAN FROM ETHANOL IN SEA WATER Acinetobacter Sp. ATCC 31012 was grown in a 250 ml flask containing 40 ml filtered sea water, 0.73 g dibasic potassium phosphate [K2HPO4.3H2O], 0.24 g monobasic potassium phosphate, 0.8 g urea, and 0.8 ml absolute ethanol (2% by volume) . The medium was inoculated with 2 ml of a late exponential culture of Acinetobacter Sp. ATCC 1012 grown under similar conditions. Incubation was for 96 hours at 30 C., with gyratory shaking at 250 rpm. After removal of the cells by centrifugation at 10,000 x g for 15 minutes and dialysis against water , nalysis showed that the yield of crude a-emulsan was 120 units per ml with a specific activity of 270 units per mg. The crude a-emulsan contained 13% total ester content when measured by the hydroxamic acid test, assur,- ing the average equivalent weight of the fatty acid esters to be 230. 13.3. PREPARATION OF -EMULSAN FRO FATTY ACID SALTS The following procedure has ben fcurd to be advantageous for producing a-emulsans from fatty acid salt substrates, such as sodium palmitate, in a 60-liter fermenter. This procedure will vary, depending upon the particular fatty acid salt or fatty acid salt mixture used as the primary carbon source. To a 60-liter fermenter fitted with four battles and a variable-speed agitator are added 733.6 g of dibasic potassium phosphate [K2HPO4.3H2O], 240 g of monobasic potassium phosphate, 8 s of magnesium sulfate [MgSO4.7H2O], 160 g of ammonium sulfate and a sufficient amount of deionized water to make 40 liters. The medium is sterilized for 40 minutes at 121'C., after which from 1% to 5% by weight of the fatty acid or fatty acid mixture (in the form of their salts) are added. The final pH of the medium is 6.9. Growth is initiated with 2 liters (5%) of a late exponential culture of Acinetobacter Sp. ATCC 31012 grown unde similar fermentation conditions. The fermentation is conducted at 300C., with aeration maintained at 15 liters of air per minute and agitation at 250 rpm. The pH of the fermentation broth should be maintained between pH 6.2 and 6.7 by the dropwise addition of concentrated ammonium hydroxide, which should require approximately 185 ml of concentrated ammonium hydroxide during the first 30 hours. Throughout the fermentation, foam is controlled by automatic pulse additions ot a silicone defoamer (Dcw Corninc izable, diluted 1:8), in connection with which an aggregate of about 50 ml ore or less will be added during Uie first 30 hours. Commencing at the 11th hour of fermentation, additional amounts of the fatty acids are continuously added to the fermentation br at d suitable rate to maIntain growth. Ammonium sulfate is periodically added to the fermentation broth at an approp)'iate rate, generally about 2 g per hour, for the first 30 hours. Maximum growth is obtained between 24 to 30 hours after inocuiation. The yield of a-emulsan will vary, depending upon the fatty acid substrate, with a cell mass of approximately two times (dry weight basis) per liter based on the emulsan yield. Analysis of tise crude a-emulsan, which can be performed on the crude extracellular fluid following extensive dialysis against water, will show that it contains a total ester content of about 9% or higher using the hydroxamic acid test and assuming that the average molecular weight of the fatty acid esters was 230. 13.4. PREPARATION OF c-EMULSAN FROM SODIUM [MgSO4.7H2O], Acinetobacter Sp. ATCC 31012 was grown in an aqueous medium containing 18.34 mg/ml of dibasic potassium phosphate FK2HPO4.3H20 ] , 6 mg/ml of monobasic potassium phosphate, 0.2 mg/ml of magnesium sulfate 9% equivalent 4 mg/ml of ammonium sulfate and 1.2 mg/ml of sodium palmitate. Growth was initiated by inoculating 0.1 ml of a washed cell suspension into 4¯ ml of the medium in a 250 ml flask. Incubation was for 72 hours at 30 C., with gyrotary shaking at 250 rpm. After removal of the cells and extensive dialysis of the crude extracellular fluid against water, analysis showed tflae, the yield of the a-emulsan was 111 units per ml with a sE,ecZfic activity of 116 units per mg determined by the standard assat technique. Tlle crude a-enulsan contained qc total ester content when measured by the hydroxamic acid test, assuming the average equixraiont weight of the fatty acid esters to be 230. 13.5. PREPARATION OF SEMULSAIx' FROM HEXADECANE Using the medium describes above in Section 13.2 with 0.2 mg/ml of hexadecane being substituted as the primary assimilable carbon source in place of sodium palmitate, Acinetobacter Sp. ATCC 31012 was grown at 30 C. for 72 hours, it gyrotary shaking at 250 rp. As before, growth was initiated by inoculating 0.1 ml of a washed cell suspension into 40 ml of the medium; in a 250 ml flask. After removal of the cells and extensive dialysi: of the crude extracellular fluid against water, analysis showed that the yield of the B-emulsan was 16 units per ml with a specific activity of 50 units per mg determined by the standard assay technique. The crude k-emulsan contained almost 5% total ester content when measured by the hydroxamic acid test, assuming the average equivalent weight of the fatty acid esters to be 230. The corresponding apo-6-emulsan, obtained by hot phenol extraction in accordance with the deproteinization technique described below in Section 13.5, contained an ester content between 2 to 3% when measured by the hydroxamic acid test. 13.6. PREPARATION OF APO-a-EMULSAN Various samples of emulsan contain between 5t to 15% protein by weight, which reflects the degree of purity of the bioemulsifier. In order to ascertain whether or not the protein moeity was essential for emulsifying activity, c c-emulsan which had been prepared by growing Acinetobacter Sp. ATCC 31012 on an ethanol medium was deproteinized by the hot phenol method described by 0. Westphal et al. in the monograph edited by R. L. Whistler, "Carbohydra-t & ChemistLytt Academic: Press, lic., New York, 1965, pp. 83-91. One gram of such. a-emulsan, dissolved in 200 ml water with the aid of a few drops of concentrated ammonium hydroxide, was brought to 65-680C. and then added to an equal volume of 90% phenol which had been preheated to 65 C. The mixture was stirred vigorously for 15 minutes at 65 C. and then cooled to 10 C. in an ice bath. The resulting emulsion was centrifuged at 5,000 x 9 for 30 minutes. After transferring the viscous aqueous phases two a flask, the remaining phenol layer and interface were extracted three rore times with 200 ml water. The combined water extracts were dialyzed extensively against several changes of distilled water and then freeze-dried to obtain 850 mg (85t yield) of apo-a-emulsan as a white fluffy solid. The remaining phenol fraction and interphase were suspended in water, dialyzed extensively against distilled water and freeze-dried, yielding 100 mg (10% yield) of a yellowish proteinaceous material which represents the denatured protein derived from such a-emulsan. The ability of each of these fractions to emulsify gas-oil was then determined using the standard assay technique. Emulsion formation was measured in 125 ml flasks containing 7.5 ml Tris-Mg buffer [200 m tris-(hydroxy methyl)aminomethane hydrochloride, pH 7.4; 10 ml: magnesium sulfate] 0.05 ml Gacl-Saran gas-oil and either 75 mcg of o-emuisan, 75 mcg of apo-a-emulsan or 15 racz of the denatured protein obtained b phenol extraction of such elsan. Flasks were agitated by reciprocal shaking (150 strokes per minute) for one hour at 26 C. Contents of the flasks were then transferred to Klett tubes for measurement of turbidity in a Klett-Summerson colorimeter fitted it a green filter. The results of these tests are summarized in Table XII, the specific activity (reported in units per mg dry weight) having been determined fro the standard curve (Curve 1-B) shown in FIG. 1. TABLE XII Emulsification of Gas-Oil Specific Activity Fraction Amount (mcg) (units per mg) a-Emuls:-n 75 276 Denatured protein 15 0 Apo-a-Enulsan 75 146 The data contained in Table XII show that all of the emalsifying activity is in the O-lipoacyl heteropolysaccharide and that none of the activity is associated with tft-e denatured protein fraction, which is also the result obtained when the temulsan is prepared from a fatty acid salt (sodium palmitic) rather than ethanol. From additional experimental work on apo-a emulsa, , it was found that, addition of 0.2 and 2.0 mcg/m ] of thi denatured protein to 10 mcg/ml of apo-a-emulsan resulted in 25% and 66% "stimulations" of emulsifying activity, respectively, which actually is a measure in the amount of turbidity obtained in the standard emulsifier assay which, in turn, is believed to be related to emulsify- ing activity. This increase in turbidity of hydrocarbon substrate when protein was added to apo-a-emulsan was not specific to the denatured protein derived by phenol extraction of a-emulsan, since different proteins, such as bovine serum albumin, lysozyme, hexokinase and denatured alcohol dehydrogenase, also result in increased turbidities in the emulsification of gas-oil when such proteins are added to apo-&alpha;-emulsan. 13.7. PREPARATION OF APO-ss-EMULSAN The hot phenol method of O. Westphal et al., supra, may also be used to extract the associated protein contained in ss-emulsan and thereby form the corresponding apo-ss- emulsan. Using the experimental method described above in Section 13.4, the ss-emulsan which had been prepared by growing Acinetobacter Sp. ATCC 31012 on a hexadecane medium was deproteinized to form the corresponding apo-ss-emulsan. All of the emulsifying activity was found to be in the O-lipoacyl heteropolysaccharide and none of such activity was found to be associated wit the denatured protein fraction. 1 3. 8. PREPARATION OF p-EMULSAN Mild base hydrolysis of eulsans will 0deacylate the lipopolysaccharide without affecting the N-acyl groups, which technique may be used to prepare the y-emulsans. Ten milliliters of an aqueous solution containing 2.5 mg/ml of a-emulsan were treated with an equal volume of 0.2 M NaOH at 98 C. for 2 hours. The solution swaC then cooled in an ice bath and carefully neutralized to pH 7.C. The neutralized solution was extensively dialyzed against water and lyophilized, yielding 20 mg (808) of #-emulsan having a Specific Emulsification Activity of 76 units per mr,,? The total ester content of the #-emulsan was 1% by the hydroxamic acid test. The reduced viscosity of this #-emulsan was 317 cc/gram. 13.9. PREPARATION OF PROEMULSAN Base hydrolysis of the &alpha;-emulsans, ss-emulsans or their apoemulsans will completely O-deacylate and partially N-deacylate the biopolymer, hydrolyzing any asociated protein at the same time. The resultant products are the proemulsans. Fifty mg of apo-a-emulsan in 30 ml of 2% KOH in methanol solution were left at room temperature for 96 hours. After removal of the methanol at low pressure, 15 ml of water were added and the pH adjusted to pH 2.0. Tbe free fatty acids were removed by ether extraction, and the aqueous solution was dialyzed and lyophilized, yielding 37 mg (74%) of proemulsan. The ester content of the proemulsan, as assayed by the hydroxamical acid test, was zero. Moreover, the product has no emulsification activity when assayed by the standard emulsification test. Elemental analysis: C 36.5%, H 7.0t, N 6.58. 13.10. PURIFICATION OF a-EMULSAN BY PRECIPITATIO LTIi1, AMMONIUM SULFATE late exponential culture (1:1000 dilution) of Acinetobacter Sp. ATCC 31012 was grown at 30 C. in a New Brunswick 14-liter fermenter using an aqueous medium contanning 14 9 per liter of dibasic acid potassium phosphate [K2HPO4.3H2O], 6 g per liter of monobasic potassium phos phate, 0.2 9 per liter of magnesium sulfate [MgSO4.7H2O], 4 9 per liter of ammonium sulfate and 20 ml per liter of absolute ethanol. The fermentation was conducted using aeration at about 15 liters per minute and agitation at 100 rpm without baffles, adding ethanol as required. When the fermentation had proceeded about 3 days, the medium was allowed to cool and 1750 g of ammonium sulfate were added slowly, with stirring, directly to 10-liters of cooled fermentation broth without prior removal of the cells (30% ammonium sulfate saturation). After standing overnight, the supernatant fluid was collected by decanta tion. The precipitate was suspended in 30% saturated ammonium sulfate and centrifuged at 10,000 x g for 15 minutes. The combined supernatant fluids were further clarified by passage through a thin layer of Kieselgel. To the cell-free supernatant fluid was added an additional portion (62 g per liter) of ammonium sulfate to reach a final concentration of 40% saturation. The resulting precipitate, collected by centrifugation at 10,000 x g for 15 minutes, was dissolved in 200 ml of water, extracted with ether, dialyzed against distilled water and lypophilized. The yield of a-emulsan was 2.1 g from 10-liters of fermentation broth, with a Specific Emulsification Activity of 330 units per mg. The same purification technique has been used to purify Q-emulsans grown on a fatty acid salt substrate. 13.11. PURIFICATION OF &alpha;-EMULSAN BY PRECIPITATION WITH QUATERNARY AMMONIUM SALTS One gram ¯, crude a-emulsan was dissolved in 100 ml of water to yield a clear viscous solution. Twenty milliliters of a 5% w/v aqueous solution of cethyltrimethyl ammonium bromide was added with mixing at room temperature. After allowing the precipitate to aggregate a few minute" the mixture was centrifuged at 5,00C x g for 10 minutes. The pellet fraction, which containe' all the emulsifying activity, was washed once with distilled water. The washed cetyltrimethyl ammonium bromide precipitate was dissolved in 100 ml of 0.1 M sodium sulfate. A small amount of precipitate remaining was removed by centrifugation at 10,000 x g for 3U minutes. One gram of potassi iodide was then added to the clear solution with mixing. The cetyltrimethyl ammonium iodide precipitate that formed was removed by centrifugation at 10,000 x g for 15 minutes. The remaining supernatant fluid was dialyzed extensively against distilled water and lypohilized to yield a white solid. This material had a Specific Emulsification Activity of 350 units per mg. A sample of the CTAB-purified &alpha;-emulsan was subjected to acid hydrolysis at 98 C. in 5 M HC1 for 6 hours to liberate any glucose that may have been present in the biopolymer. The hydrolyzed material was then analyzed by thin layer chromatography on a cellulose F plate; silver nitrate staining showed only a trace of glucose, probably as an impurity. 13.12. PURIFICATION OF ss-EMULSAN HEPTANE PARTITIONING Using the medium described above in Section 13.8 with 0.2% (v/v) hexadecane being substitutes as the primary assimilable carbon source in place of ethanol, Acinetobacter Sp. ATCC 31012 was grown at 30 C. in New Brunswick 14-liter fermenters for 4 days. Twenty-seven liters of the hexadecane-grown cul- ture were cooled an the cells removed by centritugation in a Sorvall KSB continuous flow centrifuge. The supernatant fluid was then extracted twice with 1/3 volume of ether. Xesil ether in the aqueous asess was removec by bubbling with filtered nitrogen gas. The phase ether t,ase contained no measurable emulsifying activity and was discarded. The aqueous phase was filtered successively through 3, 1.2, 0.8 and 0.45 micron Millipore filters, and the clear filtrate was then extracted four times with 0.15 volume heptane. Approximately 109 of the emulsifying activity which remained in th.e aqueous phase was discarded. The heptane fraction were combined and evaporated to a yellow syrup in vacuo. After extraction with ether, the syrup was dissolved in 1U3 ml of 50% aqueous methanol. The resulting viscous solution was dialyzed against sever changes of distilled water and lyoplized. The yield of lyophilized ss-emulsan was 1.5 g, with an extraordinarily high specific activity r,- 2,05 units per mg. A sample of this material was subjected to base hydrolysis for 72 hours at cm temperature, using an aqueous solution oE 90% methanol containing 2,58 KOH. After removal of the methanol in vacuo, addition of water and acidification to pH 1, the fatty acids were extracted with ether, methylated with diazomethane and were toen subjected to gas chromatographic analysis. The chromatograph revealed the presence of 2-hydroxydodecanoic acid (A) and 3-hydroxydodecanoic acid (ss), in a weight ratio of A/B equal to 0.83. ?l'he came purification technique "'a; be used to purify a-emulsans prepated by growing Acinetobacter Sp. ATCC 31012 rn a fatty salt acid, except that tloe medium should be first acidified so that excess fatty acid substrate may be extracted by a suitable solvent prior to solvent (i.e., heptane) partitioning. 13.13. AMMONIUM SULFATE FRACTIONATION OF APO-&alpha;-EMULSAN The phenol extraction method described above in Section 13.4 was repeated on 820 mg of &alpha;-emulsan. After three phenol extractions, the combined water extracts were extracted four times with an equal volume of ether to remove residual phenol. Following evaporation of ether, the viscous aqueus phase was cooled to 5 C and brougth to 32.5% ammonium sulfate saturation, no precipitation having formed at 308 saturation. After standing for one hour at "C., the clear translucent precipitate was collected by centrifugation at 5,000 X g for 30 minutes at 5 CC. The procedure was repeated to obtain slightly turbid second precipitate between 32.5% and 35% saturation and another small precipitate between 35% and 40% saturation. No additional precipitate formed between 40% and 60% saturation. Each of the precipitates was dissolved and was dialyzed at 2-50C. successively against distilled water, 0.05 N hydrochloric acid (24 hours) and double distilled water. The same procedure was also followed with' the remaining 60% saturated solution. Each of the resulting solutions remaining after such purification was freeze-dried and analyzed. The results of such analyses are set forth in Table XIII. The analytical data contained in Table III shox tat over 99 of the emulsifying activity of apo--emulsan preci-- tated in the two fractions between 30% and 35% ammonium sul- fate saturation. These two apo-&alpha;-emulsan fractions were characterized by similar Specific Emulsification Activities and had the same proportions of Ester, carboxylic scicl arc hexose. Moreover, both or the active fractions had high specific viscosities. one of the fractions contained sinificant quantities of protein. TABLE XIII Analyses of Ammonium Sulfate-Precipitated Fractions of Apo-&alpha;-emulsan Ammonium Sulfate Concentration (%) at which Emulsifying Carboxylic Precipi- Weight of Activity Reduced O-Ester Acid Hexose tation Precipi- Klett Specific Viscosity Protein ( moles ( moles ( moles Occured tate (mg) Units Activity (cc/g) (%) per mg) per mg) per mg) 30 - 32.5 379 66,500 175 810 0.3 0.66 1.5 0.27 32.5 - 35 194 34,500 178 570 0.15 0.63 1.5 0.33 35 - 40 25 780 31 400 0.5 0.81 - 0.20 40 - 60 82 0 0 - 0.7 - - 0.08 a/ The small amount of hexoze (glucose equivalents) which were detected are due to the presence of a small amount of a contaminating material which coprecipitated with the apo-&alpha;-emulsan, but which could be removed followig fractionation of the apo-&alpha;-emulsan with cetyltrimethyl amonnium bromide. This contaminating material was a lipopolysaccharide which contained glucose. It had no emulsifying activity when assayed by the standard emulsification technique. 13. 1 4. EMULSIFICATION OF PETROLEUM FRACTIONS BY &alpha;-EMULSABS AND ss-EMULSANS. The presence of a higher O-lipoester content in a-emulsans compared to ss-emulsans results in significant differences in the emulsification activity of these Acinetobacter biocmulsi±-iers. This conclusion was demonstrated b a series of tests which were conducted to determine the effect of both bioemulsifiers on various types of petroleum fractions which are widely used within and sold by the oil industry. In each of these tests, emulsion formation was measured in 125 ml rubber-stoppered flasks containing 5 ml of filtered sea water, 8 mg/ml of hydrocarbon and 50 mcg/ml of the particular Acinetobacter bioemulsifier, the &alpha;-emulsan having been prepare by growing Acinetobacter Sp. ATCC 31012 on an ethanol medium while the ss-emulsans was prepared by growl nag tìi* organic on a hexadecane medium. The &alpha;-emulsans were purified by the ammonium sulfate fractionation technique described above in Section 13.8 while the ss-emulsans were purified by the heptane partitioning technique described above in Section 13.10. Flasks were agitated by gyratory shaking (2Sì rpm, or by reciprocal snaking (150 strokes per minute) for n hours at 25 C. Contents of the flask were then transferred to Klett tubes for measure of turbidity in a Klett-Summerson colorimeter fitted with a green filter. Readings were taken after standing undisturbed for 10 minutes. Controls lacking either the particular Acinetobacter emulsifier or hydrocarbon yielded readings of less than 5 Klett units. The results of these tests are summarized in Table XIV. TABLE XIV Emulsification of Petroleum Fractions b &alpha;-Emulsans and ss-Emulsans Petroleum Fraction Emulsifier Emulsion (K.U.) (8 mg/ml) (50 mcg/ml) Gyratory Reciprocal Crude Oils Darius a-Emulsan 650 1090 Agha Jari a-Emulsan 720 950 Agha Jari ss-Emulsan 780 Rostam ss-Emulsan 758 Gas-Oils Darius a-Emulsan 300 800 Gach Saran &alpha;-Emulsan --- 500 Belayim Marine &alpha;-Emulsan 100 Agha Jari &alpha;-Emulsan 195 840 Agha Jari -Emulsan --- 420 Kerosenes Darius a-Emulsan 42 160 Belayim Marine a-Emulsan 35 Agha Jari &alpha; ;-Emulsan 41 110 Agha Jari ss-Emulsan --- 125 Miscellaneous Diesel Oil a-Emulsan 290 Diesel Oil ss-Emulsan --- 490 Bunker C Fuel Oil &alpha;-Emulsan --- 680 Bunker C Fuel Oil ss-Emulsan --- 35 Light Petroleum Oil ss-Emulsan --- 218 Gasoline (83 Octane) &alpha;-Emulsan --- 89 AnalyC::is of the data contained in Table XIV show that although a-emulsan and S-emulsan are both excellent emulsiflers for crude oils and are both only fair emulsifiers for kerosenes, a-emulsan is much more effective than ss-emulsan in the emulsification of gas-oils. In fact, emulsions of gas-oils were as stable as crude oil emulsions, the major reason for the higher Klett readings of crude oil emulsions than those for gas-oil emulsions being the dark color of crude oil compared to gas-oil. Bunker C fuel oil was emulsified by a-emulsan but not by 6-emulsan. Considering that the darker color of crude oil may have obscured the relative emulsification activities of both bioemulr"fiers, the data show that in general better emulsion were obtained with &alpha;-emulsan than with -emulsan and with reciprocal rather than with gyratory shaking. 13.15. EN LSIFICATIOI:4 OF MIXTURES OF PETROLEUM FRACTIONS AND PURE HYDROCARBONS BY &alpha;-EMULSAN To determn whether emulsans exhibit any specific- 'tv in ti-ie emulsification of different types of hydrocarbons, a series of tests were conducted to measure the effect of &alpha;-emulsan ,i,n the emulsifica,ic.n of mixturps of various petroleum fractions and purc hydrocarbons. In each of these tests, emulsion formation was meas- ured in 125 ml rubber-stoppered flasks containing 5 ml of filtered sea water, 8 mg/ml of total substrate (petroleum fraction plus additive) and 50 mcg of a-emulsan. All mixtures of hydrocarbons were 1:1 (v/v3. In some of the tests, fraction-s of Agha Jari crude oil were used, the fractions having been prepared by the procedure of A. Jobson et al., App. microbial 23, 1082-1089 (1972), under which procedure Fractions 1, 2 and 3 correspond to the aliphatic (saturates), aromatic and polar aromatic fractions, respectively. As before, the a-emulsan was prepared by growing Acinetobacter Sp. ATCC 31012 on an ethanol medium and was purified b the ammonium sulfate fractionation technique. However, similar results will be obtained using a-emulsans prepared by growing the organism on a fatty acid as the primary assimilable carbon source. Flasks were agitated by reciprocal shaking (150 strokes per minute) for 2 hours at 25 C. Contents of the flask were then transferred to Klett tubes for measurement of turbidity in a Klett-Summerson colorimeter fitted with a green filter. Readings were taken after standing undisturbed for 10 minutes. The results of these tests are 5" :.arized in Table XV. TABLE XV Emulsification of Mixtures of Petroleum, Fractions and Pure Hydrocarbons by &alpha;-Emulsan Petroleum Fraction Additive Emulsion (r,Li.) Kerosene none Kerosene hexadecane 6 Kerosene 2-methylnaphthalene 1050 Gasoline none , 115 Gasoline hexadecane 230 Gasoline 2-metl1ylnapthalene 1100 Agha Jari Fraction 1 none 13G Fraction 2 none 60 Fraction 3 none 1t)5 Fraction 1 Fraction 2 1050 Fraction 1 Fraction 3 1500 Fraction 2 Fraction 3 80 The data contained in Table XV show that the efficacy of a-emulsan in the emulsification of hydrocarbons is dependent on the relative concentrations of aliphatic and aromatic (or other cyclic) ccunds in tlie hydrocarbon substrate. For examplc, the ability of a-emulsan to emulsify kerosene and gasoline was enhanced greatly by 2-methylnaphthalene but not by hexadecane. The requirement that the hydrocarbon substrate contain both aliphatic and aromatic (or other cyclic) components was further supported by the results obtained In the emulsification of mixtures of column fractionated crude oil. Although crude oil itself is emulsified by a-emulsan, none of the fractions were good substrates by themselves. Mixtures containing one fraction rich i-. aliphatics (Fraction 1) and the other rich in aromatics (Fractions 2 or 3) were efficiently emulsified. 13. 16 CLEANING OT,L-CONTANINATED VESSELS Aqueous solutions in sea water or fresh 'water (the latter containing a suitable divalent cation, such as magnesium) of &alpha;-emulsans are excellent emulsifying agents for cleaning and recovering hydrocarbonaceous residues. including residual crude oll, from oil-comtaminated tankers, barges, storage tanks, tank cars and trucks, pipelines and other containers used to transport or tor crude oil For petroleum fractions. Washing the oil-con tainted surfaces of such vessels with an aqueous solution containing from about 10 mcq/ml to about 20 mg/ml of &alpha;-emulsan readily forms an oil-in-water emulsion of such hydrocarbonaceous residues provided that the solution contains from about 1 to about 100 mM, and preferably from about 5 to about 40 md, of at least one suitable divalent cation, which are normally present in sea water and "t.ard" tap water. Moreover, the &alpha;-emulsan need not be purified, since a cell-free fermentation broth containing a-emulsans resulting from growing Acinetobacter Sp. ATCC 31012 on e suitable medium can be used directly or after suitable dilution. Using the data which is set forth above in Sec tions 8 and 9, processes can be designed to clean any oil contaminated vessel and to recover the hydrocarbonaceous residue from the resultant oil-in-water emulsion, either by breaking the emulsion physically or chemically. Depending upon the amount and composition of the oil or hydrocarbon aceous residue to be cleaned, the aggregate amount of a-emulsan may be as low as 1 part by weight (dry weight basis) per 1,000 to 10,000 parts by weight of hydrocarbon, the higher concentrations of a-emulsan yielding more stable emulsions. To show the use of the cell-free fermentation broth as an emulsifying agent for such cleaning, Acineto bacter Sp. ATCC 31012 was cultivated in 15 liter glass fermenter containing 122y of dibasic potassiun phosphate [K2HPO4.3H2O], 40 g of monobasic potassium, 1.33q of magnesium sulfate [MgSO4.7H2O], 13.39 of area and deionized water Lo a final voluh of 10 liters. The medium was sterilized for 30 minutes at 191 C., after which 200 ml of absolute ethanol (2% by volume) was added. The final pH of the ethanol-salts medium was 7.0. After the medium had cooled to 30 C., 50G ml. of a late expcnen- tial culture of Acinetobacter Sp. ATCC 31012 grown in the same medium was added to the glass fermenter and the culture maintained at 30 C., with an air flow of 3.5 liters per minute and an agitation speed of 200 rpm (no baffles). During the course of fermentation the p dropped to 6.0. Throughout the fermentation, foam was controlled by periodic addition of silicone defo nle, (in the form of a spray). Under these conditions, the fermentation broth contained 260 units per ml of a-emulsan after 72 hours and 7.4 g per liter of biomass (dried at 90 C. for 16 hours). After removal of the'cells by centrifugation or filtration, the resultant cell-free fermentation broth could be used to wash crude oil from the oil-contaminated surface of a steel container which simulated the loner wall of a tank which had been emptied of crude oil. 13.17. EFFECT OF MOBILITY CONTROL POLYSACCHARIDES ON EMULSION FORMATION WITH EMULSANS The bacterial exocellular heteropolysaccharide (XANFJ; SFL 14630) produced by the Kelco Division of rck c. Co., Inc., which has been recommended as a mobility control polymer for enhanced oil recovery, was tested in varying concentrations in conjunction with 20 mcg/ml of a-emulsan to determine the effect of such material on the emulsification of gas-oil. In each of these tests, 0.1 ml of Gach-Saran gas-oil was added to 125 ml Ehrlenmeyer flasks containing 7.5 ml of Tris-Mg buffer [ 50 m tris (hydroxymethyl)aminomethane hydrochloride, pH 7.2; 10 m, magnesium chloride ] , 20 mcg/ml of a-emulsan and varying concentra.ions of the mobility control polysaccharide. Several tests were also run without the 0-emulsan to determine whether the mobility control polymer emulsified the hydrocarbon. The flasks were agitated by gyratory shaking (280 rpm) in a New Brunswick G24 incubator shaker for one hour at 30 > C. Contents of the flasks were then transferred to Klett tubes for measurement of turbidity in a Klett Summerson colorimeter fitted with a green filter. Readings were taken after standing undisturbed for 10 minutes. The results of these tests, which are summarized in Table XVI, are expressed as the percentage increase (+) or decrease (-) in the turbidity of the emulsion resulting from the addition of varying concentrations of the mobility control polymer. TABLE XVI Effect of Mobility Control Polysaccharide on Emulsion Formation Mobility Control a-Emulsan Relative Emulsifying Polysaccharide (mcg/ml) (mcc,/ml) Ability (%) 1 20 -17.0 2 20 + 3.1 5 20 - 7.3 10 20 +41.7 20 20 to27.2 40 20 +2u.6 10-150 None No Activity As snown in Table XVI, it appears that the use of the mobility control polysaccharide in conjunction with the emulsan is capable of stimulating emulsifying activity by about 40% at a concentration of 10 mcg/ml, which suggests the potential advantages for using both additives in a chemically- augmented "slug" to be injected into a petroleum reservoir for enhanced oil recovery. By itself, however, this mobility control polymer had no ability to emulsify the hydrocarbon. 13.18. ADSORPTION OF EMULSANS ON CLAYS Because of the importance 6f aluminosilicate clays, such as kaolin and bentonite, in many industrial and petroleum production and refining processes, a series of tests was conducted to determine whether emulsans adsorped onto the surface of such aluminosilicate clays. Bentonite was selected for these tests, since it contains up to 90% by weight of montmorillonite, the structure of which corresponds to the theoretical formula (OH)4SI8Al4O20.xH2O and is responsible for its high sorptive power and ion-exchange capacity. The theoretical treatment of adsorption fro a mixed solution is somewhat complicated, since it involves competition between solutes and solvents for the solid surface. In these tests, adsorption from solution was analyzed by the Freundlich equation: x=a.C1/n m where x represents the amount of solute adsorped by the mass m of solid, C represents the solute concentration anc, an n are experimentally-determined constants. Experimentally, x=(C-C)V, where C and the in and equilibrium solute concentrations, respectively, and \' is the volume of solution in contact witi the sorbent. In this case, an apparent adsorption Isotherm can be expressed if x/m is plotted against equilibrium solute concentration. In each of these tests, the emulsan used was an a-emulsan purified in accordance with the ammonium sulfate fractionation technique described above in Section 13.8. Prior to drying, the a-emulsan contained about 7t by weight of protein, about 16% by weight of ash and about 38% by weight of moisture. Aqueous solutions of this a-emulsan were prepared by dissolving the dry emulsan in 0.02M solutions of Tris-Mg buffer [20 mM tris-(hydroxymethyl)aminomethane containing 10 m magnesium sulfate]. Nanactivated, technical grade bentonite was used as the sorbent. Adsorption of a-emulsan from a given volume of solution on a given mass of bentonite was carried out in 100 ml or 50 ml Ehrlenmeyer flasks, with shaking for 1 hour at 100 strokes per minute. The equilibrium solutions were separated from the bentonite by centrifugation or filtration. Emulsan assays were performed by the standard assam technique. The results of the tests are summarized in Table XVII. TABLE XVII Adsorption of &alpha;-Emulsan on Bentonite Bentonite &alpha;-Emulsan (mg/ml) (mg) Co Cx %Bound 10 0.11 0.032 71 20 0.11 0.028 75 25 0.10 0.006 94 40 0.11 0.004 96 60 0.11 < 0.001 > 99 The data contained in Table XVIl show that the adsorption of a-emulsan to bentonite is a function of bentonite concentration. About 70% of the emulsan is adsorbed when the ratio of bentonite to emulsan is 100:1, while more than 95% of the emulsan is adsorbed at ratios of 400:1 or higher. 13.19. FLOCCULATION OF CLAYS BY EMULSANS Adsorption of emulsan on bentonite results in flocculation of suspended particles of the clay, with sedimentation occurring about 5 to 1C tines faster than in the absence of emulsan. To a solution of 50 ml sea water and 50 ml Tris buffer containing 100 mcg/ml cf a-emulsan was added 1.6 g of non-activated, technical-grade bentonite with mixing, and the resultant dispersion was then poured into a calibrated glass cylinder and allowed to settle at room temp-erature. As a control, a parallel experiment was conducted without using the a-emulsan. The results of these tests, which are graph- ically illustrated In Fig. 18, show that the dilute (1CC ppm) solution of &alpha;-emulsan enhanced the rate of sedimentation by a factor of five over that obtained in the control. More importantly, the supernatant fluid obtained following the emulsan-mediated flocculation was clear, while the supernatant fluid obtained in the control remained opal- escent even after prolonged standing. 13.20 FLOCCULATION OF CLAYS BY PROEMULSANS Promulsans are even more effective than emulsens in the flocculation of suspended particles of bentonite. Table XVII summarizes an experiment in which the flocculatln" Of 0.4 g bentonite in 14 ml of either Tris buffer, pH 7.26, or phosphate buffer, pH 6.5, was measured in the presence of a-emulsan, proemulsan and no addition. The final concentration of a-emulsan was 0.05 mg per ml, whereas the final concentration of proemulsan was 0.045 mg/ml. After vigorous shaking for 2 minutes, the suspension was centrifuged at 2,5000 rpm for 60 minutes. The data presented in Table XVIII were obtained by measuring the clarified upper layer in the centrifuge tube. Similar results were obtained with *-emulsan as with proemulsan. TABLE XVII Flocculation of Bentonite by &alpha;-Emulsan and Proemulsan Sample Volume of Clear Upper Layer (ml) PH 6.5 pH 7.26 1. No addition 1.1a 1.1 2. a a-Emulsan ! 1.8a 2.0 3, Proemulsan 3.0 4.6 The upper layer was opalescent. 13.21. BREAKING EMULSAN-INDUCED EMULSIONS Since emulsans form stable oil-in-water emul sions and, moreover, since emulsans are adsorbed onto bentonite, a series of tests were conducted to determine the behavior of such emulsan-induced emulsions in the presence of bentonite. In one test, an emulsion of Agha Jari crude oil (1 ml in 10 ml sea water) containing about 0.1 mg/ml of a-emulsan was prepared by the standard technique of adding the oil to the solution of a-emulsan in a flask and agitating the flask by gyratory shaking for one hour at room temperature. After 2 days, 1 g of preswelled bentonite was added to the stable emulsion and the dispersion was shaken intensively for about 20 seconds, after which it was transferred to a tube and allowed to settle. After 15 minutes, a breakage of the emulsion was observed. After 20 hours, two layers had separated, the upper layer being clear while the lower layer was a gel-like sediment which occupied about one-half the prior volume of the emulsion. In another test, an emulsion of Agha Jari crude oil (0.1 ml3 in 7.5 ml Tris-Mg buffer solution 150 mM tris-(hydroxymethyl)aminomethane hydrochloride, pH 7.2; 10 m31 magnesium chloride containing 0.08 mg/ml of -crulsan a as prepared by the standard technique as before. As a control, 0.1 ml ot the crude oil in 7.5 ml of buffer solution as shaken under the same condi ions Both samples were transferred to tubes containing 0. g or bentonite, shaken for 30 seconds and the contents allowed to settle. After 15 hours, there was a complete breakage of the erulsan-induced emulsion Moreover, the flocculated sediment formed in the presence of a-emulsan was two times larger by volume than the sediment from the control test. 13.22. REMOVAL OF OIL Fi^xO^, SAND BY EMULSAN One gram of white sand was preadsorbed itli either 0.1 ml, 0.2 ml, or 0.3 ml (saturated) Darius crude oil (light weight Persian crude) in duplicate. The sand samples were then transferred to 100 ml Ehrlenmeyer flasks containing 10 ml Tris-Mg buffer t50 mM ti:is-(hydroxymethyl) aminomethane hydrochloride, pH 7.2; 10 mM magnesium sulfate ] To one each of the samples containing 0.1 ml, 0.2 ml, or 0.3 ml of the crude oil was added a-emulsan at a final concentration of 0.1 mg/ml. The remaining three samples (without the emulsan) served as controls. The samples were shaken at 140 strokes per minute for 30 minutes at 30 C. in a shaking water bath. Following the shaking, the samples were allowed to settle for one hour, and the aqueous phase was separated from the sand by decantation. Each of the sand samples was washed twice with 10 ml Tris-Mg buffer, and the decanted washed fluids combined. The sand samples and the aqueous phase (together with the wash fluids) were each separately extracted with diethyl ether and the ether extract dried under nitrogen in tared flasks. Table XIX summarizes the results of these tests, where the amount of oils removed by emulsan is measured as the amount of ether-extracted material in the water phase and the amount of oil ren1aininS on the sand is measured as Xhe amount of ether-soluble material extracted from the washed sand. TABLE XVI II Effect of &alpha;-Emulsan on Removal of Crude Oil from Sand Crude Oil Emulsan Oil Removed Oil Remaining Removal on Sand (ml) (ang/ml) from Sand (ma) on Sand mg r9) 0.1 --- < 5' 65 < 1G 0.1 0.1 57 < 5 > 90 0.2 --- 15 108 sand 0.1 96 12 8 0.3 --- 33 172 16 0.3 0.2 165 14 92 The effect of a-emulsan in removing oil fror, 0.1 clearly demonstrated in Table XIX. In the presence o- 0. mg/ml, over 90% of the crude oil was removed. This is probably a lower estimate since other extraction of sand particles which had not settled before the initial separa- tion of the phases would contribute to the overall about of material extracted from the aqueous phase in the control. Very little ( < 10%) of the oil was removed without shaking. During these tests, it was observed that the solubilized oil emulsified in those samples to which &alpha;-emulsan was added. Moreover, the addition of the &alpha;-emulsan to flask containing sand and buffer prior to preadsorp- tion of the oil prevented the subsequent adsorption Df oi to the sand during the shaking. From the data contained in Table XIX, it is clear that emulsans may be used in.enhanced recovery processes for recovering oil which is contained in sand or sandstone formations, in which processes a chemically-augmented "slug" comprising water or brine and one or more added chemicals is injected into a petroleum reservoir located in a sand or sandstone formation and is displaced through the reservoir to recover crude oil. In addition, dilute solutions of emulsans (which are biodegradable) may be used in oil spill management to emulsify oil spills deposited on beach sand so that the oil may be dispersed and subsequently microbiologically degraded. 13.23. REMOVAL OF OIL FROM LIMESTONE BY EMULSAN A series of tests was conducted to determine the ability of emulsan to remove oil from limestone, since enhanced oil recovery processes based on chemical flooding of petroleum reservoirs located in reservoir formations (in which processes a chemically-augmented "slug" of water or brine and one or more added chemicals is injected into a petroleum reservoir in d limestone formation and is displaced through the reservoir to recover crude' oil) '?ili require efficient eniulsifitrs capable of removing oil from limestone, which chemically is calcium carbonate. Four 4-gram samples of calcium carbonate (crushed limestone) were each preadsorbed with 0.8 g Aghi Jari crude oil. The oil-impregnated limestone samples were then transferred to 100 ml Ehrlenmeyer flasks containing 20 ml Tris-Mg buffer [50 m tris-(hydroxymethyl)aminomethane hydrochloride, pH 7.2; 10 mP1 magnesium sulfate ] To each of three of the samples was added varying amounts of a-emulsan (2, 5 and 10 mg, respectively) while the remaining sample (without the emulsan) served as a control, The samples were shaken at 140 strokes per minute for 30 minutes at 30 C. in a Tuttenaucer shaking water bath. Following the shaking, the samples were allowed to settle for 1 hour, and the aqueous phase was separated from the limestone by decantation. Each of the limestone samples was washed twice with 10 ml Tris-Mg buffer, and the decanted washed fluid combined. The limestone samples and the aqueous phase (together with the wash fluids) were each separately extracted with diethyl ether and 'the ether extract. dried under nitrogen in tared flasks. Table XIX summarizes the results of these tests, where the amount of oils ,-+ oved by emulsan is measured as the amount of ether-extracted material in the water phase and t amount of oil remaining on the limestone was' calculated by difference. TABLE XIX Effect of &alpha;-Emulsan on Removal of Crude Oil from Limestone Sample Emulsan Oil Removed Oil Remaining Removal (mg/ml) (q) (q) (t) A --- -0.06 0.74 - 14 B 0.1 0.71 0.09 89 C 0.25 0.74 0.0b 93 D 0.5 0.78 0.02 98 The effect of remulsan in removing oil from limestone is clearly demonstrated in Table XV. In the presence of 0.1 mg/ml, over 898 of the crude oil was removed; at a-emulsan concentrations of 0.5 mg/ml, over 98% of the crude oil was removed. As in the case of the tests described above in Section 13.20, this is probably a lower estimate since ether extraction of limestone particles which had not settled before the initial separation of the phases would contribute to the overall amount of material extracted from the aqueous phase in the control. Because emulsans and particularly the c-emulsans on a weigt-for-weigt basis are very efficient oil-inwater emulsifiers and because these extracellular lipopolysaccharides tolerate relatively high concentrations of sodium chloride without losing their emulsification activity, it is expected that emulsans will be widely used in all enhanced oil recovery techniques for freeing oil from limestone formations. It will be understood that where the expresoon "between.....and....." or "between.....to....." is used. this includes the upper and lower .its of e range specified. Tt is alsoto be understood that the specific and preferred features disclosed for one aspect of the invention are wherever appropriate also applicable to other aspects of the invention,

Claims: CLAIMS 1. An extracellular microbial lipopolysaccharide our a derivative thereof selected from the group consisting of (a) the extracellular microbial proteinassociated lipopolysaccharides (herein collectively called "&alpha;-emulsans") producible by Acinetobacter Sp. ATCC 31012 or amutant thereof, in which the lipopolysaccharide components (herein collectively called "apo-a-emulsans") are completely N-acylated and partially O-acylated heteropolysaccharides made up of major amounts of D-galactosamine and an aminouronic acid, such apo-Q- emulsans containing at least 5 percent by weight of fatty acid esters in which (1) the fatty acids contain from about 10 to about 18 carbon atoms; and (2) substantially 50percentby weight or more of such fatty acids are composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid; (b) the deproteinized extracellular microbial lipopolysaccharides (herein collectively called "apo-aemulsans") obtainable from the a-emulsans producible by Acinetobacter AS. 31012or a mutant thereof, the apo-o- emulsans being completely N-acylated and partially 0-acylated heteropolysaccharides made up of major amounts of D-galactosamine and an aminouronic acid, the apo-a-emulsans containing at least 5 percent by weight of fatty acid esters in which (1) the fatty acids contain from about 10 to about 18 carbon atoms; and (2) substantially 50 percent by weight or more of such fatty acids are composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid; (c) the deproteinized extracellular microbial polysaccharides (herein collectively called "apo-Q- emulsans") obtainable from the ss-emulsans producible by Acinetbbacter Sp. ATCC 31012 or amutant thereof, the apo-ss- emulsans being completely N-acylated and partially 0-acylated heteropolysaccharides made up of major amounts of D-galactosamine and an aminouronic acid, the apo-ss-emulsans containing less than 5 percent by weight of fatty acid esters in which (1) the fatty acids contain from about 10 to about 18 carbon atoms; and (2 less than 50 percent by weight of such fatty acids are composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid; (d) the 0-deacylated extracellular proteinassociated microbial polysaccharides (herein collectively called the "*-emulsans")obtainnble from the emulsansproducible by Acinetobacter Sp. ATCC 31012 or a mutantthereof,the protein-free components of such *-emulsans being completely N-acylated heteropolysaccharides made up of major amounts of D-galactosamine and an aminouronic acid and containing from 0 to 1 percent by weight of fatty acid esters in which, when present, the fatty acids contain from about 10 to about 18 carbon atoms; ; (e) the deproteinized 0-deacylated extracellular microbial polysaccharides (herein collectively called the "apo-ç-emulsans) derivable from a-emulsans, B-emulsans, *-emulsans, apo-a-emulsans, or apo-ss-emulsans, the apo-1-emulsans being completely N-acylated heteropolysaccharides made up of major amounts of D-galactosamine and an aminouronic acid and containing from 0 to 1 percent by weight fatty acid esters in which, when present, the fatty acids contain from about 10 to about 18 carbon atoms; ; (f) the deproteinized 0-deacylated extracellular microbial polysaccharides (herein collectively called the "proemulsans") derivable from a-emulsans, 8-emulsans, *-emulsans, apo-a-emulsans, apo-ss-emulsans or apo-9-emulsans, the proemulsans being poly[D-galactosamine/aminouronic acid] bio polymers in which (1) none of the hydroxy groups are acylated; and (2) from none to all of the amino groups are acyclated; and (g) the divalent metal, ammonium and quaternary ammonium salts of such &alpha; -emulsans, apoz -emulsans, apo- f3-emulsans, 4)-emulsans, apo-W-emulsans and proemulsans. 2. Extracellular microbial protein-associated lipopolysaccharides (herein collectively called "a-emulsans") produced by Acinetobacter Sp. ATCC 31012 oramutantthereof, in which the lipopolysaccharide components (herein collectively called "apo-a-emulsans") are completely N-acylated and partially 0-acylated heteropolysaccharides made up of major amounts of D-galactosamine and an aminouronic acid, such apo-a-emulsans containing at least 5 percent by weight of fatty acid esters (1) in which the fatty acids contain from about 10 to about 18 carbon atoms; and (2) sis stantially 50 percent by weight or more of such fatty acids are composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid; 3. a-Emulsans according to claim 2, in which the aggregate fatty acids contained in the 0-lipoacyl portion of the apo-a-emulsan components have an average equivalent weight from about 200 to about 230. 4. a-Emulsans according to claim 2, in which the apo-a-emulsan components contain from 5 to 7 percent by weight of fatty acia esters in which the aggregate fatty acids have an average equivalent weight from about 200 to about 230. 5. a-Emulsans according to claim 2, in which the apo-&alpha;-emulsan components contain from 7 to 14 percent by weight of fatty acid esters in which the aggregate fatty acids have an average equivalent weight from about 200 to about 230. 6. a-Emulsans according to claim 2, in which the apo-a-emulsan components contain from 14 to 19 percent by weight of fatty acid esters in which the aggregate fatty acids have an average equivalent weight from about 200 to about 230. 7. a-Emulsans according to claim 2, in which the apo-a-emulsan components contain from 0.5to O.7micromoles per mi'Iligaam of fatty acid esters in which from substantially 50 to substantially 70 percent by weight of such fatty acids are composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid. 8. a-Emulsans according to claim 2, in which the apo-a-emulsan components are composed of from 20 to 35 percent by weight of D-galactosamine; from 30 to 35 percent by weight of hexosamineuronic acid; and from 7 to 19 percent by weight of fatty acid esters in which the fatty acids contain from about 10 to about 18 carbon atoms and are characterized by an average equivalent weight from about 200 to about 230, fnmn substantially 50 to substantially 70 percent by weight of such fattyacids inthe O-lipaacyl portion of the apo-a-emulsan components being composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid. 9. a-Emulsans according to claim 2, in which the reduced viscosity of the Q-emulsan is 480 + 50 cc/g between pH 3 to pH 8.5. 10. o-Emulsans according to claim 2, in which the weight average molecular weight of the apo-a-emulsan components is about one million. 11. a-Emulsans according to any of claims 2, 3, 4, 5, 6, 7, 8, 9, or 10, in which the a-emulsans are characterized by a Specific Emulsification Activity of 200 units per milligram or higher, where one unit per milligram of Specific Emulsification Activity is defined as that amount of emulsifying activity per milligram of bioemulsifier which yields 100 Klett absorption units using a standard hydrocarbon mixture consisting of 0.1 ml of 1:1 (v/v) hexadecane/2-methylnaphthalene and 7.5 ml of Tris-Mg buffer. 12. a-Emulsans according to any of claims 2, 3, 4, 5, 6, 7, 8, 9 or 10, in which the ratio of 2-hydroxydodecanoic acid to 3-hydroxydodecanoic acid in the 0lipoacyl portion of the apo-o-emulsan components is in the range from 1:4 to 1:1. 13. a-Emulsans according to any of claims 2, 3, 4, 5, 6, 7, 8, 9 or 10, in which the ratio of 2-hydroxydodecanoic acid to 3-hydroxydodecanoic acid in the 0-lipoacyl portion of the apo-a-emulsan components is in the range from 1:4 to 1:2. 14. Extracellular microbial lipopolysaccharides (herein collectively called "apo-a-emulsansA) comprising the deproteinized lipopolysaccharides obtained from the a-emulsans produced by Acinetobacter Sp. ATCC 31012 art mutant thereof, the apo- eemulsans being completely N-ac,ylated and partially 0-acylated heteropolysaccharides made up of major amounts of D-galactosamine and an aminouronic acid and containing at least 5 percent by weight of fatty acid esters (1) in which the fatty acids contain from about 10 to about 18 carbon atoms; (2) substara1l,y S percentby weight or more of such fatty acids are composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid; 15. AF)O-Q-emulsans according to claim 14, in which the aggregate fatty acids contained in the 0-lipoacyl portion of such apo-a-emulsans have an average equivalent weight from about 200 to about 230. 16. ApO-a-emulsans according to claim 14, in which the 0-lipoacyl portion of such apo-a-emulsans contains from 5 to 7 percent by weight of fatty acid esters in which the aggregate fatty acids have an average equivalent weight from about 200 to about 230. 17. Ao-a-emulsans according to claim 14, in which the 0-lipoacyl portion of such apo-a-emulsans contains from 7 to 14 percent by weight of fatty acid esters in which the aggregate fatty acids have an average equivalent weight from about 200 to about 230. 18. Apo-&alpha;-emulsans according to claim 14, in which the 0-lipocyl portion of such apo-a-emulsans contains from 14 to 19 percent by weight of fatty acid ester# in which the aggregate fatty acids have an average equivalent weight from about 200 to about 230. 19. Apo-&alpha;-emulsans according to claim 14, in which the 0-lipoacyl portion of such apo-a-emulsans contain from 0.5 to 0.7 micromoles per milligram of fatty acid esters in which fray substantially 50 to substantially 70percentbv weigh of such fatty acids are composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid. 20. Apo-u-emulsans according to claim 14, in which the heteropolysaccharides are composed of from 20 to 35 percent by weight of D-galactosamine; from 30 to 35 percent by weight of hexosamineuronic acid; and from 7 to 19 percent by weight of fatty acid esters in which the fatty acids contain from abcut 10 to, about 18 carbon atoms and are characterized by an average equivalent weight from about 200 to about 230, from substantially 50 substantially 70 percent by weight of such fatty acids in the 0-lipoacyl portion of such apo-a-emulsans eing composed of 2-hydroxydodecanoic acid and 3-hydroxy edecanoic acid. 21. Apo-cremulsans according to any of claims 14, ,, 16, 17, 18, 19, 20, characterized by a Specific mulsificatiion Activity of 100 units per milligram higher, where one unit per milligram of Specific mulsification Activity is defined as that amount of emulsifying activity which yields 100 Klett absorption units using a standard hydrocarbon mixture consisting of 0.1 ml of 1:1 (v/v) hexadecane/2-methylnaphthalene and 7.5 ml of Tris-Mg buffer. 22. Apo-a-emulsans according to any of claims 14, 15, 16, 17, 18, 19, or 20, in which the ratio of 2-hydroxydodecanoic acid to 3-hydroxydodecanoic acid in the 0-lipoacyl portion of such apo-a-emulsans is in the range from 1:4 to 1:1. 23. Apo- -emulsans according to any of claims 14, 15, 16, 17, 18, 19, or 20, in which the ratio of 2-hydroxydodecanoic acid to 3-hydroxydodecanoic acid in the 0-lipoacyl portion of such apo-a-emulsans is in the range from 1:4 to 1:2. 24. The deproteinized extracellular microbial polysaccharides (herein collectively called "apo-a- emulsans") obtained from the Femulsans produced by Acinetobacter Sp. ATCC 31012 or a mutant thereof, the apof emulsans being completely N-acylated and partially 0-acylated heteropolysaccharides made up of major amounts of D-galactosamine and an aminouronic acid, the apo-B- emulsans containing less than 5 percent by weight of fatty acid esters in which (1) the fatty acids contain from about 10 to about 18 carbon atoms; and (2) less than 50 percent by weight of such fatty acids are composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid. 25. Apo-ss-emulsans according to claim 24, in which the aggregate fatty acids contained in the 0-lipoacyl portion of such apo-ss-emulsans have an average equivalent weight from about 200 to about 230. 26. Apo-ss-emulsans according to claim 24, in which the heteropolysaccharides are composed of from 20 to 35 percent by weight of D-galactosamine; from 30 to 35 percent by weight of hexosamineuronic acid; and less than 5 percent by weight of fatty acid esters in which the fatty acids contain from about 10 to about 18 carbon atoms and are characterizeo by an average equivalent weight from about 200 to about 230, less than 50 percent by weight of such fatty acids in the 0-lipoacyl portion of such apo--emulsans being composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid. 27. Apo-emulsans according to claim 24, in which the ratio of 2-hydroxydodecanoic acid to 3-hydroxydodecanoic acid in the 0-lipoacyl portion of such apo-- emulsans is in the range from 1:4 to 1:1. 28. Apo-ss-emulans according to claim 24, in which the ratio of 2-hydroxydodecanoic acid to 3-hydroxydodecanoic acid in the 0-lipoacyl portion of such apoE emulsans is in the range from 1:1.25 to 1:1. 29. The 0-deacylated extracellular proteinassociated microbial polysaccharides (herein collectively called "#-emulsans") obtained from the emulsans produced by Acinetobacter Sp. ATCC 31012 ora mutant thereof, the -rotein-free components of such +-emulsans being completely -acylated heteropolysaccharides made up of major amounts of D-galactosamine and an aminouronic acid and containing .rom 0 to 1 percent by weight of fatty acid esters in which, when present, the fatty acids contain from about 10 to about 18 carbon atoms. 30. iP-Emulsans according to claim 29, characterized by a Specific Emulsification Activity of substantially one-half that of a-emulsans, where one unit of Specific Emulsification Activity is defined as that amount of emulsifying activity which yields 100 Klett absorption units using a standard hydrocarbon mixture consisting of 0.1 ml of 1:1 (v/v) hexadecane/2-methylnaphthalene and 7.5 ml of Tris-Mg buffer. 31. The deproteinized 0-deacylated extracellular microbial polysaccharides (herein collectively called the "apo- Wemulsans") derived from either a-emulsans, -emulsanc, &commat;-emulsans, apo-a-emulsans, or apo-ss-emulsans, the apo-it'- emulsans being completely N-acylated heteropolysaccharides made up of major amounts of D-galactosamine and an aminouronic acid and containing from 0 to 1 percent by weight of fatty acid esters in which, when present, the fatty acids contain from about 10 to about 18 carbon atoms 32. The deproteinized 0-deacylated extracellular microbial polysaccharides (herein collectively called the "proemulsans") derived from either a-emulsans, 8-emulsans, +-emulsans, apo-a-emulsans, apo-iB-emulsans or apo-ç-emulsans, the proemulsans being poly[D-galactosamine/aminouronic acid] biopolymers in which (1) none of the hydroxy groups are acylated; and (2) from one to all of the amino groups are acylated. 33. Polyanionic heteropolysaccharide biopolymers in which (a) substantially all of the sugar moieties are N-acylated aminosugars, a portion of which is N-acylated-Dgalactosamine and another portion of which is N-acylated aminouronic acid, a part of the N-acyl groups of such heteropolysaccharide being N-3-hydroxydodecanoyl groups; and (b) at least 0.2 micromoles per milligram of such heteropolysaccharide consisting of fatty acid esters in which (1) the fatty acids contain about 10 to about 18 carbon atoms and (2) substantially 50 percent by weight or higher of such fatty acids are composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid. 34. Polyanionic heteropolysaccharide biopolymers according to claim 33, in which the heteropolysaccharide is in the form of a salt of a divalent cation. 35. Polyanionic heteropolysaccharide biopolymers according to claim 33, in which the heteropolysaccharide is in the form of its magnesium salt. 36. Polyanionic heteropolysaccharide biopolyners according to claim 33, in which the heteropolysaccharide biopolymer is complexed with a protein. 37. An emulsifying agent comprising an aqueous solution containing (A) at least 10 mc/ml of the extracellular microbial protein-associated lipopolysaccharides (herein collectively called "&alpha;-emulsans") produced by Acinetobacter SD. ATCC 31012 or a mutant thereof, in which the lipopolysaccharide components (herein collectively called "apos - emulsans") are completely N-acylated and partially 0-acylated heteropolysaccharides made up of major amounts of D-galactosamine and an aminouronic acid, of such apo-a- emulsans containing at least 5 percent by weight of fatty acid esters in which (1) the fatty acids contain fro about 10 to about 18 carbon atoms; and (2) substantially 50 percent by weight or more of such fatty acids ar composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid; and (B) from 1 to 100 m of at least one divalent cation. 38. An emulsifying agent according to claim 37, in which the apo-&alpha;-emulsan components of the emulsans contain from 5 to 19 percent by weight of fatty acid esters. 39. An emulsifying agent according to claim: 37, in which the apo-a-emulsan components of the ci-emulsans contain from 5 to 19 percent by weight of fatty acid esters in which the aggregate fatty acid have an average equivalent weight from about 200 to about 230. 40. A process for producing extracellular microbial lipopolysaccharides which comprises () inoculatig an aqueous fermentation medium containing a growthsustaining amount of ethanol with a culture of Acinetobacter Sp. ATCC 31012 or amutant thereof' (B) aerobically the microorganism in such fermentation medium, while adding additional amounts of ethanol to sustain growth, for a period of time sufficient to produce extracellular microbial protein-associated lipopolysaccharides (herein collectively called "a-emulsans") in which the lipopolysaccharide components (herein collectively called "apo-aemulsans") of such a-emulsans are N- and O-lipoacylated heteropolysaccharides made up of major amounts of Dgalactosamine and an aminouronic acid, such apo-a-emulsans containing at least 5 percent by weight of fatty acid esters in which (1) the fatty acids contain from about 10 to about 18 carbon atoms; and (2) substantially SO percent by weight or more of such fatty acids are composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid; and (C) separating substantially all of the microbial cell mass from the emulsan-containing culture medium. 41. A process for producing a-emulsans according to claim 40 in which the fermentation medium contains (1) a greater than growth-sustaining amount of at least one assimilable nitrogen-containing compound; and (2) a growth-sustaining amount of one or more assimilable phosphorus-containinq, compounds. 42. A process for producing a-emulsans according to claims 40 or 41, in which (1) substantially all of the microbial cell mass is separated from the emulsan-containing culture medium by filtration, centrifugation or decantation; (2) the cell-free emulsan-containing culture medium is extracted with a water-immiscible organic solvent capable of concentrating substantially most of the emulsans at the solvent/water interface, thereby partitioning the emulsans between the solvent/water interface; and (3) the emulsans are recovered from such solvent/water interface. 43. A process for producing a-emulsans according to claims 40 or 41, in which (1) after removal of the microbial cell mass, the emulsans are concentrated in a partially-saturated solution of an ammonium salt and the concentration of ammonium salt in such solution is increased until the emulsans precipitate out of such solution; (2) the salted-out emulsan-containing precipitate is dissolved in water and impurities are removed by solvent extraction or by dialysis; and (3) the resultant purified emulsan is recovered from such solution. 44. A process for producing extracellular microbial lipopolysaccharides which comprises (A) inoculating an aqueous fermentation medium containing from 1.25 to 3 percent (v/v) of ethanol with ; culture of Acinetobacter Sp. ATCC 31012 or a mutant thereof: : (B) aerobically growing the microorganism in such fernentat ion medium, while adding additional amounts of ethanol to sustain growth, aerating the fermentation medium sufficiently to give an oxygen flow rate of 190 millimoles per liter per hours or higher, and maintaining the pH of the fermentation medium in the range from 6.2 to 6.7 and the temperature of the fermentation medium in the range from 25 C. to 35 C., for 2 period of time sufficient to produce extracellular microbial protein-associated lipopolysaccharides (herein collectively called "a-emulsans") in which the lipopolysaccharide components (herein collectively called "apon emulsans") are N- and 0-lipoacylated heteropolysaccharides composed of (i) from 20 to 35 percent by weight of D-galactosamine; (ii) from 30 to 35 percent by weight of an aminouronic acid; and (iii) from 7 to 19 percent by weight of fatty acid esters in which the fatty acids contain from about 70 to about 18 carbon atoms and are characterized by an average equivalent weight from about 200 to about 230, from subdtarrtially 50to svi > - stantially 70 percent by weight of such fatty acids being composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid; and (C) separating substantially all of the microbial cell mass from the emulsan-containing culture medium. 45. A process for producing semulsans in accordance with claim 44, in which the fermentation medium contains (1) a greater than growth-sustaining amount of at least one assimilable nitrogen-containing compound; and (2) a growth-sustaining amount of one or more assimilable phosphorus-containing compounds. 46. A process for producing extracellular microbial lipopolysaccharides which comprises (A) inoculating an aqueous fermentation medium containing a growthsustaining amount of one or more fatty acid salts with a culture of Acinetobacter Sp. ATCC 31012 or a mutant thereof; (B) aerobically growing the microorganism in such fermentation medium., while adding additional amounts of such fatty acid salt or salts to sustain growth, for a period of time sufficient to produce extracellular microbial proteinassociated lipopolysaccharides (herein collectively called "a-emulsans") in which the lipopolysaccharide components (herein collectively called "apo-a-emulsans") of such a-emulsans are N- and 0-lipoacylated heteropolysaccharides made up of major amounts of D-galactosamine and an aminouronic acid, such apo-a-emulsans containing at least 5 percent by weight of 0-substituted fatty acid esters in which (1) the fatty acids contain from about 10 to about 18 carbon atoms; and (2) substantially peKxnt by weight or more of such fatty acids are composed of 2hydroxydodecanoic acid and 3-hydroxydodecanoic acid; and (C) separating substantially all of the microbial cell mass from the emulsan-containing culture medium. 47. A process for producing a-emulsans according to claim 46, in which tbe carbon source is one or more assimilable fatty acid salts wherein the fatty acid(s) contain from 10 to 18 carbon atoms and are selected from saturated fatty acids, unsaturated fatty acids and hydroxy-substituted fatty acids. 48. A process for producing a-emulsans according 1 laim 46 in which the fermentation medium contains (1) a water than growth-sustaining amount of at-least one .--imilable nitrogen-containing compound; and (2) a h-sustaining amount of one or more assimilable sonorus-containing compound. 49. A process for producing a-emulsans according any of claims 46, 47, or 48, in which (1) substantially aml of the microbial cell mass is separated from the emulsan-containing culture medium by filtration, centrifugation or decantation; (2) after removal of excess fatty salt substrate, the cell-free emulsan-containing -ture medium is extracted with a water-immiscible Organic sen capable of concentrating substantially most of the emulsans at the solvent/water interface thereby partitioning the emulsans between the solvent/water interface; and (3) the emulsans are recovered'from such solution. 50. A process for producing a-emulsans according to any of claims 46, 47, or 48, in which (1) after removal of the microbial cell mass, the emulsans are concentrated in a partially-saturated solution of an ammonium salt and the ccrcentration of ammonium salt in such solution is increased until the emulsans precipitate out of such solution; (2) the salted-out emulsan-containing precipitate is disso'-ved in water and impurities are removed by solvent extraction or by dialysis; and (3) the resultant purified enulsan is recovered from such solution. 51. A process for producing extracellular microbial lipopolysaccharides which comprises (A) inoculating an aqueous fermentation medium containing a growthsustaining amount of the assimilable salts of one or more fatty acids with a culture of Acinetobacter Sp. ATCC 31012 or a mutant thereof: (B) aerobically growing the microorganism in such fermentation medium, while adding additional amounts of such fatty acid salt or salts to sustain growth, aerating the fermentation medium sufficiently to give an oxygen flow rate of 190 millimoles per liter per hours or higher, and maintaining the pH of the fermentation medium in the range from 6.2 to 6.7 and the temperature of the fermentation medium in the range from 25 C. to 35 C., for a period of time sufficient to produce extracellular microbial protein-associated lipopolysaccharides (herein collectively called "a-emulsans") in which the lipopolysaccharide components (herein collectively called "apo-aemulsans") are N- and 0-lipoacylated heteropolysaccharides composed of (i) from 20 to 35 percent by weight of D-galactosamine; (ii) from 30 to 35 percent by weight of hexosamineuronic acid; and (iii) from. 7 to 19 percent by weight of fatty acid esters in which the fatty acids contain from about 10 to about 18 carbon atoms and are characterized by an average equivalent weight from about 200 to about 230, fnm substantially 50tosubstantially 70 percent by weight of such fatty acids being composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid; and (C) separating substantially all of the microbial cell mass from the emulsan-containing culture medium. 52. A process for cleaning hydrocarbonaceous residues, including residual petroleum, from oil-contaminated tankers, barges, storage tanks, tank cars and trucks, pipelines and other containers used to transport or store crude oi1 or various petroleum fractions, which comprises (A) washing the oil-contaminated surfaces of such vessels with an emulsifying agent comprising an aqueous solution containing (1) at least 10 mcg/ml of the extracellular microbial protein-associated lipopolysaccharides (herein collectively called "a-emulsans") produced by Acinetobacter Sp. ATCC 31012 or amutant thereof, in which the lipopolysaccharides components (herein collectively called "apo-a-emulsans") are N- and O-lipoacylated heteropolysaccharides made up of major amounts of D-galactosamine and an aminouronic acid, such apo-a-emulsans containing at least 5 percent by weight of O-substituted fatty acid esters in which (i) the fatty acids contain from about 10 to about 18 carbon atoms; and (ii) more than 50 percent by weight of such fatty acids are composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid; and (2) at least 5 mM of at least one divalent cation thereby forming an oil-in-water emulsion of such hydrocarbonaceous residues; and (B) removing such oil-in-water emulsion from the washed vessel. 53. A cleaning process according to claim 52, in which the concentration of the a-emulsans is in the range of from 10 mcg/ml to 100 mg/ml. 54. A cleaning process according to claim 53, in which the concentration of the a-emulsans is- in the range of from 10 mcg/ml to 20 mg/ml. 55. A cleaning process according to claim 54, in which the concentration of the a-emulsans is in the range of from 50 mcg/ml to 10 mg/ml. 56. A cleaning process according to any of claims 52 to 55, in which the divalent cation is magnum (mug++) in concentrations in the range from 5 to 40 mM. 57. A cleaning process according to any of claims 52 to 56, in which the aqueous solution is a solution in sea water. 58. A process for cleaning and recovering hydrocarbonaceous residues, including residual petroleum, from oil-contaminated tankers, barges, storage tanks, tank cars and trucks, pipelines and other containers used to transport or store crude oil or various petroleum fractions, which comprises (A) washing the oil-contaminated surfaces of such vessels with an emulsifying agent comprising an aqueous solution containing ('1) at least 10 mcg/ml of the extracellular microbial protein-associated lipopolysaccharides (herein collectively called "a-emulsans") produced by Acinetobacter Sp. ATCC 31012 or a mutant thereof, in which the lipopolysaccharide components (herein collectively called "apo-a-emulsans") are N- and O-lipoacylated heteropolysaccharides made up of major amounts of D-galactosamine and an aminouronic acid, such apo-aemulsans containing at least 7 percent by weight of fatty acid esters in which the fatty acids contain from about 10 to about 18 carbon atoms and are characterized by an average equivalent weight from about 200 to about 230, from substantially 50 to substantially 70 percent by weight of such fatty acids being composed of 2-hydroxydodecanoic acid and 3-hydroxydodecanoic acid; and (2) from 1 to 100 mM of at least one divalent cation, thereby forming an oil-in-water emulsion of such hydrocarbonaceous residues: (B) removing such oil-in-water emulsions from the cleaned vessel; and (C) recovering the hydrocarbonaceous residues from such oil-in-water emulsion. 59. A process according to claim 58, in which the concentration of the a-emulsans is in the range of from 10 mcg/ml to 100 mg/ml. 60. A process according to claim 59, in which the concentration of the a-emulsans is in the range of from 10 mcg/ml to 20 mg/ml. 61. A process according to any of claims 58 to 60, in which the aqueous solution is a solution in sea water. 62. A salt of an a-emulsan, apo-a-emulsan, apo p-emulsan, -emulsan, apo- -emulsan or proemulsan, which emulsans, apoemulsans, N-emulsans, apo-w-emulsans and proemulsans are as specified in claim 1. 63. A process for producing extracellular microbial lipopolysaccharides which comprises (A) inoculating an aqueous fermentation medium containing a growthsustaining amount of a medium which promotes the production of a-emulsan by Acinetobacter Sp. ATCC 31012 or a mutant thereof with a culture of Acinetobacter Sp. ATCC 31012 or a mutant thereof; (B) aerobically growing the microorganism in such fermentation medium, while adding additional said medium to sustain growth, for a period of time sufficient to produce extracellular microbial proteinassociated lipopolysaccharides (herein collectively called "a-emulsans") in which the lipopolysaccharide components (herein collectively called "apo-a-emulsans") of such a- emulsans are N- and O-lipoacylated heteropolysaccharides made up of major amounts of D-galactosamine and an aminouronic acid, such apo-a-emulsans containing at least 5 percent by weight of fatty acid esters in which (1) the fatty acids contain from about 10 to about 18 carbon atoms; ; and (2) subsaantiay SOpercentby weight or more of such fatty acids are composed of 2-hydroxydodecanoic acid an- 3hydroxydodecanoic acid; and (C) separating substantially all of the microbial cell mass from the emulsancontaining culture medium. 64. A process for producing a-emulsans according to claim 63 in which the fermentation medium contains (1) a greater than growth-sustaining amount of at least one assimilable nitrogen-containing compound; and (2) a growth-sustaining amount of one or more assimilable phosphorus-containing compounds. 65. A process for producing a-emulsans according to claims 63 or 64, in which (1) substantially all of the microbial cell mass is separated from the emulsancontaining culture medium by filtration, centrifugation or decantation: (2) the cell-free emulsan-containing culture medium is extracted with a water-immiscible organic solvent capable of concentrating substantially most of the emulsans at the solvent/water interface, thereby partitioning the emulsans between the solvent/water interface: and (3) the emulsans are recovered from such solvent/water interface. 66. A process for producing -emulsans according to claims 63 or 64, in which (1) after removal of the microbial cell mass, the emulsans are concentrated in a partially-saturated solution of an ammonium salt and the concentration of ammonium salt in such solution is increased until the emulsans precipitate out of such solution: (2) the salted-out emulsan-containing precipitate is dissolved in water and impurities are removed by solvent extraction or by dialysis: and (3) the resultant purified emulsan is recovered from such solution. 67. An emulsifying agent according to any of claims 37 to 39, in which the concentration of the a-emulsans is in the range of from 10 mcg/ml to 100 mg/ml. 68. An emulsifying agent according to claim 67, in which the concentration of the -emulsans is in the range of from 10 mcg/ml to 20 mg/ml. 69. An emulsifying agent according to any of claims 37, 38, 39, 67 and 68, which is an aqueous solution in sea water.

Inventors: BELSKY, IGAL, GUTNICK, DAVID L., ROSENGERG, EUGENE, SHABTAI, YOSSEF, ZOSIM, ZINAIDA
Applicants: PETROLEUM FERMENTATIONS N.V.
Application year: 1980
Main classification: C12P21
IPC codes: C02F1, C09K8, C12P19, C07H3, C07H7, C12R1, B01F17, C12P1, B01D21