bluuebunny/crossref_metadata_2025 huggingface dataset:
Some effects of turbine size on novobiocin fermentations
Authors: Steel R. , Maxon W. D.
Published: December 2004

Studies were made of oxygen transfer and power in 20‐1. novobiocin fermentations with five sizes (23–60% of the tank diameter) of geometrically similar flatblade turbine impellers. The influence of changes in apparent viscosity on oxygen transfer and power was found to be related to impeller diameter. At constant agitator speed the oxygen availability rate (OAR) decreased with increase in apparent viscosity, but the magnitude of the reduction was less with a small impeller than with a large one. At constant power input the small‐diameter impeller (23% of tank diameter) gave an OAR about 8 times that of the large one (60% of tank diameter) when tested in viscous beer, whereas with sulfite or yeast all impeller diameters gave the same OAR. Impeller tip velocity correlated with OAR independently of diameter for the five turbine sizes examined. The power required for optimal novobiocin yields increased with increase in turbine diameter, but the yields were independent of diameter at equal OAR.
Plastic ampoules for liquid smallpox vaccine
Authors: Espmark Åke , Lindner Stig
Published: December 2004

Manufacturing of plastic (PVC) single‐dose ampoules for liquid smallpox vaccine is described. The green stained vaccine is injected in polyvinyl chloride tubes which are then sealed by high frequency welding to make ampoules of 16 mm. length. The tendency for desiccation of the filled vaccine at elevated temperature is considered as an advantage, since it provides a visible indication of previous improper storage. The ampoule is opened by cutting with scissors and vaccine is squeezed out directly on the skin.
Continuous chemical sterilization of microbiological media with β‐propiolactone
Authors: Toplin Irving
Published: December 2004

A laboratory bench set‐up for the continuous chemical sterilization of microbiological media using β‐propiolactone was developed. The apparatus permits the sterilization of up to 4 liters/hr. of liquid media. The parameters of hydrolyzing time and temperature necessary to reduce the β‐propiolactone to nontoxic levels were determined using a E. coli‐nutrient broth system. The sterilization technique was applied successfully to a variety of media, and its potential usefulness on an industrial scale is discussed.
Automatic control of dissolved oxygen levels in fermentations
Authors: Siegell Stuart D. , Gaden Elmer L.
Published: December 2004

Dissolved oxygen levels in fermentation systems are affected by (a) gas flow rate, (b) degree of agitation, and (c) oxygen partial pressure in the gas. Since the first two variables cannot easily be separated, a method for dissolved oxygen control has been devised based on the variation of oxygen partial pressure in the gas. Oxygen and nitrogen are fed to a special mixing valve capable of varying the proportions of the two gases while keeping the total flow rate constant. A dissolved oxygen electrode and control system adjust the valve setting to automatically maintain a preset oxygen level. Oxygen analyzers, monitoring the inlet and outlet gas streams, provide additional information from which oxygen absorption and uptake rates may be determined. The system provides a means for the quantitative and independent study of aeration and agitation effects. In addition, it offers a basis for routine control of oxygen levels in plant fermentation equipment.
Stripping in sparged fermentation systems. II. The effect of operating temperature and gas phase pre‐humidification in an ethanol‐water system
Authors: Hamer G.
Published: December 2004

The effect of operating temperature upon relative stripping of a two component (ethanol–water) mixture by dry air, with the aid of a previously derived equation,1 is considered. The variations encountered in the relative humidity of air sparged to fermentors are discussed. A general equation is developed for the stripping of a more volatile component from a solution in water by wet air. The theoretical results derived from this equation are tested experimentally at one particular level of prehumidity of the air sparged to an ethanol–water system.
Kinetic studies of gluconic acid fermentations
Authors: Humphrey Arthur E. , Reilly Peter J.
Published: December 2004

The kinetics of the gluconic acid fermentation have been studied at pH 5.8 Pseudomonas ovalis B‐1486 was used as the fermenting organism. D‐Gluconolactone was found as an intermediate in the fermentation and accumulated at times in large amounts. When this occurred, hydrolysis of the lactone was found to be the rate limiting reaction. This can be, under certain conditions, a poor fermentation in which to study oxygen transfer limiting conditions. Further, it is impossible to relate batch and continuous kinetic data for this fermentation unless the lactone hydrolysis reaction is taken into account.
Submerged production of arginine decarboxy‐oxidase in 20‐liter and 200‐liter fermentors
Authors: Delcambe L. , Pho Dang Ba , Regnouf F. , Olomucki A.
Published: December 2004

A process has been developed whereby arginine decarboxy‐oxidase (ADO) can be produced by growing Streptomyces griseus in submerged form in 20‐l. and 200‐l. tank fermentors. A medium containing salts, corn steep, glucose, or starch is used. With addition of 0.02% arginine and with limited aeration, a high yield has been obtained.
Location and action of Streptomyces griseus α‐D‐mannosidase, an antibiotic‐transforming enzyme
Authors: Inamine Edward , Demain Arnold L.
Published: December 2004

Streptomyces mannosidase, like the enzyme from other sources, is shown to require a divalent cation for enzyme activity. N‐Ethylmaleimide pretreatment of enzyme‐containing cells eliminated the requirement of aeration for enzyme activity. Methyl‐α‐D‐mannoside was found to be a strong inhibitor of the hydrolysis of both p‐nitrophenyl‐α‐D‐mannoside and mannosidost reptomycin. The enzyme is bound at or near the surface of the cell and is inactivated by sonic oscillation. Small participate matter containing most of the activity can be released from the cells into water, such release being inhibited by phosphate, Tris, or sodium chloride.
Proteases of the genus Bacillus. II. Alkaline proteases
Authors: Keay Leonard , Moser Patricia W. , Wildi Bernard S.
Published: December 2004

The alkaline proteases of B. subtilis NRRL B3411, B. pumilis, and B. licheniformis have been isolated by fractionation followed by ion exchange chromatography and their homogeneity demonstrated. General enzyme properties of the B. sublitis NRRL B3411 alkaline protease have been studied and attempts made to differentiate a group of alkaline proteases. It is clear that the alkaline proteases known as Subtilisins or Subtilopeptidases are not, exclusive to B. subtilis but are common to many Bacilli and therefore the generic name Bacillopeptidases has been proposed. It is clear too that on the basis of the effect of pH on activity, amino acid composition, esterase activity, and immunological cross‐reactions the Bacillopeptidases can be divided into two groups or types: (a) Bacillopcptidase A (Subtilisin A or Subtilopeptidase A) which includes Subtilisin Carlsberg, B. licheniformis, and B. pumilis alkaline proteases; (b) Bacillopeptidase B (Subtilisin B or Subtilopeptidase B) which includes B subtilis NRRL B3411, Subtilisin Novo, Subtilisin BPN' (Nagarse), alkaline protease Daiwa Kasei, and (probably) B. subtilis var. amylosacchariticus. At present, no further differentiation is possible and whether or not the enzymes within group A or B are identical remains an open question. Methods for examination of crude enzyme mixtures or fermentation beers are described and from the examination of a number of crude enzymes and fermentation beers it appears that organisms producing Bacillopeptidase A do not produce neutral protease or amylase, while organisms producing Bacillopeptidase B produce a neutral protease and amylase as well.
Kinetics of the conversion of glucose to gluconic acid by Pseudomonas ovalis
Authors: Bull Daniel Newell , Kempe Lloyd L.
Published: December 2004

The concept of a “critical oxygen concentration” is conventionally considered to hold for the submerged aerobic fermentation of glucose to gluconic acid. Above the critical level the fermentation rate is supposedly independent of oxygen concentration. In this work it is shown that, at a given agitation rate, the fermentation is independent of dissolved oxygen when above the critical. However, an increase in the agitation rate results in an increase in the fermentation rate. This increase was shown to be accompanied by an increase in the gluconolactone concentration in the broth. Gluconolactone, an intermediate in the reaction pathway, is hydrolyzed nonenzymatically to gluconic acid. Evidence is presented to suggest that the increased gas‐liquid interfacial area brought about by increased agitation causes an increased net rate of lactone formation. This in turn results in an increased rate of hydrolysis of the lactone to gluconic acid. A model is presented hypothesizing that negatively charged cells adsorb at the gas‐liquid interface. These cells attract hydrogen ions, causing a lowering of the pH in the film around the bubbles. It is this lowered pH which is considered to bring about increased fermentation rates when the interfacial area is increased. Supporting evidence is presented.
Microbiological leaching of a zinc sulfide concentrate
Authors: Torma A. E. , Walden C. C. , Branion R. M. R.
Published: December 2004

The microbiological extraction of zinc from a high‐grade zinc sulfide concentrate has been investigated, using a pure strain of Thiobacillus ferrooxidans. Conditions such as temperature, pH, pulp density, nutrient, concentration, and specific surface of solids have been studied in terms of their effects on zinc extraction rate and in some instances on final zinc concentration in solution. Where appropriate, optimum conditions for leaching have been specified.
Utilization of bound lactase in clinical chemistry
Authors: Stasiw R. O. , Patel A. B. , Brown H. D.
Published: December 2004

A “stick test” for the detection of lactose has been developed based upon the enzyme lactase chemically bound via Procion brilliant orange to DEAE‐cellulose. Utilization of the bound rather than the free enzyme allows an ease in its addition to and removal from the reaction medium as well as a facile control of reagent quality and quantity. The bound enzyme “stick” may be reused for several determinations.
Continuous production of extracellular protease by Bacillus subtilis in a two‐stage fermentor
Authors: Jensen Donald E.
Published: December 2004

Growth and protease production of Bacillus subtilis in semisynthetic and synthetic media were studied in batch culture and in a two‐stage, laboratory scale, continuous fermentor. The amount, of extracellular protease production was measured under specific growth conditions in both stages of the ferment or. At the dilution rates employed, the cells in the first stage of the ferment or produced negligible quantities of protease, and the culture primarily functioned as a continuous inoculum for the second stage of the fermentor. The culture effluent from the second stage of the fermentor contained extracellular protease, on the average, equal to 60 per cent, of the activity that had been found in the supernatant of a 48‐hr batch culture grown in a medium having the same composition as that in the continuous fermentor. Extracellular protease was produced in semisynthetic medium by B. subtilis in the two‐stage fermentor for as long as 20 days without culture degeneration. Additional studies indicated that continuous protease production could also be achieved in a synthetic medium. The RNA/ protein ratios of cells grown in semisynthetic medium in batch culture and in each stage of the two‐stage fermentor were examined. There was a positive correlation between the amount of protease produced by the cells and their RNA/ protein ratio. Techniques employed for continuous production of protease by B. subtilis and the potential use of the method for investigating the control of secondary metabolite synthesis are discussed.
Preparation and characteristics of microcapsules containing asparaginase
Authors: Mori Takao , Sato Tadashi , Matuo Yuhsi , Tosa Tetsuya , Chibata Ichiro
Published: December 2004

Conditions for the preparation of microcapsules containing asparaginase by interfacial polymerization were investigated.

The activity of microcapsules prepared under the optimal conditions was about 37% compared with that of native asparaginase. Particle size of microcapsules could be controlled by determining the stirring rate and concentration of Span 85. The membranes of microcapsules were resistant to mechanical shock or attack of chymotrypsin, and no leakage of asparaginase from microcapsules was observed.
The “rotary column” method for growth of large‐scale quantities of cell monolayers
Authors: Santero Giovanni G.
Published: December 2004

A method and an apparatus that reduce the heavy expenses involved in traditional methods for the large‐scale monolayer production of primary and secondary, strain and line cells and of the biologicals derived therefrom are described. The method is based on the principle of gathering in a single unit a sheaf of columns by means of general manifolds fitted with cocks. The growth of cells on the glass walls is irrespective of the number, length, and diameter of the columns used. The apparatus, placed in a thermo‐adjustable room and connected to adequate devices which allow it to rotate on its longitudinal axis and to be set in a vertical position, need not be dismounted nor transported since it can be connected by a number of tubes to the necessary services. Sterilization is carried out by flowing steam and fluids are poured in or drained off by vacuum or pressure. A microscope fitted to the bearing structure allows the operator to observe the cell monolayers and the cytopathic effect of viruses on the whole length of the outer columns. During the various working stages pH is under continuous control and automatically adjusted. The whole working cycle is extensively described (cleaning, sterilization, seeding, incubation, trypsinization of the monolayer, culture and harvesting of the virus) and results compared with those obtained by traditional methods.
Mannose‐containing polysaccharides of yeasts
Authors: Spencer J. F. T. , Gorin P. A. J.
Published: December 2004

The known species of yeasts produce at lest 180 different polysaccharides having mannose as a major constituent. The type of mannan formed is characteristic of the yeast species, and can be used as an aid in identification and classification. The immunological characteristics of yeasts depend largely upon the nature of the mannans. Some of the yeast mannans can be produced in relatively high yields, and have been suggested as replacements for plant and bacterial gums as thickeners, dispersing agents, and similar applications. However, more significant uses, based on the finer differences in their chemical structures and the specific reactions they undergo, may result from a closer study of these polymers.
The relationship of substrate, growth rate, and maintenance coefficient to single cell protein production
Authors: Abbott Bernard J. , Clamen Allen
Published: December 2004

Various organic compounds were assessed as potential substrates for single cell protein production. Substrate evaluation was based on the costs associated with the substrate, oxygen, and heat yield coefficients: Ysub, Yo, and Ykcal, respectively. Yo, and Ykcal, were calculated from experimental values of Ysub, and from the elemental composition of bacterial cells. The dependence of the yield coefficients on the specific growth rate (μ) and maintenance coefficient (m) also was assessed. The analysis disclosed that m caused two‐ to threefold variations in the yield coefficients as μ was increased from 10% to 100% of μmax. The effect of different m values at constant specific growth rates also was determined. The value of m had a significant effect on the yield coefficients even at high specific growth rates. Assignment of cost factors to the yield coefficients provided an estimation of the impact m and μ on biomass production costs.
Kinetic analysis of diauxic growth and pectolytic enzyme formation in aspergilli
Authors: Zeteliaki‐Horvåth Kornélia , Békåssy‐Molnår Erika
Published: December 2004

Kinetic studies on the growth of Aspergillus strains as well as constitutive and inductive polygalacturonase formation have been made in bath fermentations, without pH control. Equations describing growth and product formation of the four‐stage growth of microorganisms were applied for the first time to diauxic growth and enzyme formation of Aspergillus strains. Diauxic growth of the cultures has been found in both sucrose‐ and peetin‐containing media. Enzyme concentration in the second transient phase, calculated by the use of new equations, proved to be negligible. In the exponential and declining phases, the calculated values of mycelial and enzyme concentrations were in good agreement with the values observed. Types of classification of the product formation of Luedeking and Piret refer to the second cycle of diauxie. The types of product formation described by Kono and Asai and Luedeking and Piret are mostly in good agreement with each other. The greatest difference has been found in the case of inductive endo‐polygalacturonase formation, where the final enzyme formation could not be plotted because of the decrease (autolysis) in mycelial weight.
Maturity and product formation in cultures of microorganisms
Authors: Brown D. E. , Vass R. C.
Published: December 2004

The concept of a maturation time (tm) for a product formation by a microbial culture is developed and a simple method is described for determining this parameter and also the product formation rate constant (kp) from batch culture experiments. The concept has been utilized in a general model for the prediction of steady state product concentrations in single‐stage continuous‐flow culture systems.
Hydrolysis of β‐galactosides using polymer‐entrapped lactase. A study towards producing lactose‐free milk
Authors: Dahlqvist Arne , Mattiasson Bo , Mosbach Klaus
Published: December 2004

A yeast lactase, Maxilact, was immobilized in crosslinked polyacrylamide using a bead‐polymerization technique. The polymer beads obtained, containing the entrapped enzyme, were used for the preparation of lactose‐free milk. The binding yield of the enzyme and residual enzymic activity in the “enzyme beads” were studied as a function of the amounts of monomeric acrylamide and cysteine and bovine serum albumin present as protecting agents in the monomer‐enzyme solution prior to polymerization. A maximum of about 75% of the enzyme could be immobilized using a 20% (w/v) solution of acrylamide plus N, N′‐methylenebis‐acrylamide, whereas the highest activity quotient (bound to free) of about 60% was observed on using a 25% solution. The presence of cysteine increased the activity by up to 30% and that of serum albumin up to about 15%.
Dextranase production from Penicillium funiculosum
Authors: Kosaric N. , Yu K. , Zajic J. E. , Rozanis J.
Published: December 2004

Twenty‐eight Penicillium cultures were screened for dextranase activity. Dextranase yield of about 2000 DU/ml was obtained with Penicillium funiculosum SH‐5. Maximum dextranase concentration was attained only when cell mass decreased. The kinetics of the dextranase production was correlated with the cell mass by a two‐parameter model. The optimum pH and temperature for dextranase were 5.0‐5.5 and 55°C, respectively. Crude dextranase preparation was inhibitory to insoluble glucan formation by streptococcus mutans 6715 in vitro.
The kinetics of yeast growth on pure hydrocarbons
Authors: Blanch H. W. , Einsele A.
Published: December 2004

The kinetics of C. tropicalis growth were investigated with pure n‐hexadecane as dispersed phase substrate. Two distinct growth phases were found: In the first phase, exponential growth was independent of stirrer speed. The onset of the second phase, one of linear growth, was determined by stirrer speed. By the use of two different fermenter types, it was shown that the drop size of the dispersed phase was not primarily responsible for the observed kinetics. It was considered that the formation of biological flocs determined the observed growth pattern. This was substantiated by the results of continuous cultures in the different fermenter types, with various substrate concentrations.
Glutamic acid production with gel‐entrapped Corynebacterium glutamicum
Authors: Slowinski Wlodzimierz , Charm Stanley E.
Published: December 2004

A glutamic acid producing microorganism (Corynebacterium glutamicum) is entrapped in a polyacrylamide gel. These immobilized microorganisms were used to produce glutamic acid in successive batches of fresh medium. Free microorganisms similarly used produced much less glutamic acid under similar conditions.
Effect of aeration intensity on the biochemical composition of baker's yeast. I. Factors affecting the type of metabolism
Authors: Oura Erkki
Published: December 2004

Efforts were made to eliminate the influence of other factors as far as possible in order to obtain reliable results on the effects of oxygen on the growth of baker's yeast. A cultivation method is presented which permits the study of the effects of aeration intensity under conditions where the influence of catabolite repression is eliminated. A completely synthetic medium with glucose as the only carbon and energy source is also described.

The capacity of yeast to perform aerobic metabolism varies when cultivated under different intensities of aeration. A clear maximum is observed for growth with 10% oxygen in the aerating gas mixture. Under conditions where catabolite repression does not function yeast has the potential for oxidative metabolism even under oxygen‐limited growth. The main agent controlling the ability of yeast to support growth using only the oxidative metabolism is the available oxygen.

At high oxygen tensions the metabolism is disturbed.
The tubular loop batch fermentor: Basic concepts
Authors: Russell T. W. F. , Dunn I. J. , Blanch H. W.
Published: December 2004

A tubular loop batch fermentor has been designed and constructed, and was found to behave in a similar manner to a conventional stirred tank reactor. It appeared that foaming could be greatly reduced as no air ever encountered the impeller. The fluid mechanics of pipe flow are considerably simpler than tank flow patterns. On this basis a design procedure for a large scale tubular fermentor was outlined, which had considerable advantages over the more complex scale‐up problems of a tank fermentor.
Preparation of immobilized enzymes from acrylic monomers under γ‐ray irradiation
Authors: Maeda H. , Suzuki H. , Yamauchi A. , Sakimae A.
Published: December 2004

Immobilized glucoamylase, invertase, and β‐galactosidase were prepared by using 2‐hydroxyethyl acrylate and dimethylacrylamide under γ‐ray irradiation. In the case of 2‐hydroxyethyl acrylate, the monomer‐enzyme solution was changed to the gel by irradiation of less than 1.0 Mrad, but it was difficult to eliminate enzyme leakage from the gel. When leakage was eliminated by increased irradiation, the activities of the gels were very low. In the case of dimethylacrylamide, the monomer–enzyme solution was changed to a gel by irradiation of 1.0 Mrad; leakage could be eliminated by irradiation of 2.0 Mrad. This gel possessed very high activity. In the case of acrylic acid‐sodium acrylate, the monomer–enzyme solution could not be changed to a gel. In preparing gels, high concentrations of enzyme protein had a tendency to obstruct gelation.
High productivity tank fermentation for gramicidin S synthetases
Authors: Tzeng Chu H. , Thrasher Kathleen D. , Montgomery John P. , Hamilton Bruce K. , Wang Daniel I. C.
Published: December 2004

A high productivity tank fermentation for gramicidin S synthetases has been developed to supply biocatalyst for a preparative‐scale ATP‐driven cell‐free enzymatic synthesis employing the polypeptide antibiotic, gramicidin S, as a model product. A rich, complex medium supports rapid and dense growth of the enzyme‐producing microorganism, Bacillus brevis ATCC 9999, accompanied by the appearance of excellentenzyme activities. Under conditions used, the two enzyme fractions of the gramicidin S synthesizing system, as well as the total enzymatic activity for synthesis of gramicidin S, all reach their maxima simultaneously at the point where growth enters the stationary phase. Successful batch enzyme fermentations have been performed at the bench (14 liter) and pilot (180 liter)scales.
Conversion of L‐sorbose to L‐sorbosone by Gluconobacter melanogenus
Authors: Kitamura I. , Perlman D.
Published: December 2004

Growing cultures, washed cells, and cell‐free extracts of Gluconobacter melanogenus IFO 3293 were found to convert L‐sorbose to L‐sorbosone. The product was identified by thin layer chromatography of the 2, 4‐dinitrophenylhydrazone, and by paper partition chromatography using chemically prepared materials as standards. Factors influencing the conversion included incubation temperature and composition of the growth medium. Addition of betaine or choline to the growing cultures stimulated conversion of L‐sorbose to L‐sorbosone.
Further studies on the mechanism of cell disruption by extreme pressure extrusion
Authors: Brookman James S. G.
Published: December 2004

The use of another air operated extreme pressure hydraulic pump fitted with either a needle valve or a simple microbore tube is described, together with the figures obtained for the soluble protein released from suspensions of commercially obtained baker's yeast (Saccharomyces cerevisiae). The theory of the mechanism is also discussed.
Oxygen transfer to mixed cultures in tower systems
Authors: Hsu Kenneth H. , Erickson Larry E. , Fan Liang‐Tseng
Published: December 2004

A modified dynamic method is introduced to determine the oxygen transfer coefficient, KL a, in aerobic fermentation systems which are not mechanically agitated. The dissolved oxygen concentration is measured continuously following a step down or a step up in aeration rate. The response curve is analyzed to obtain the value of KLa

Experiments were carried out at several different air flow rates using mixed culture in concurrent tower fermentors with motionless mixers. The effect of sieve trays and Koch motionless mixers on oxygen transfer was investigated using a 3 in. diameter column. The values of KL aobtained at the bottom of each column were found to be higher than those obtained at the top. Comparison of the results showed that the values ofKL a were higher when the Koch mixers were used than when the sieve trays were employed.

The oxygen uptake rate by the organisms rX, is also calculated by using the KL a values obtained. They compare favorably withthe experimentally measured values.
Immobilized‐enzyme continuous‐flow reactor incorporating continuous electrochemical regeneration of NAD
Authors: Coughlin Robert W. , Aizawa Masuo , Alexander Bruce F. , Charles Marvin
Published: December 2004

Electrochemical regeneration of the cofactor nicotinamide adenine dinucleotide (NAD) from its reduced form (NADH) has been coupled with the alcoholdehydrogenation reaction which consumes NAD and produces NADU using alcohol dehydrogenase bound to alumina. Alcohol (reactant) is added directly to the system while aldehyde (product) leaves the system through an ultrafiltration membrane which prevents loss of the cofactor. This system provides a continuous‐flow process for carrying out a cofactor‐requiring enzymatic reaction with no net loss or consumption of enzyme or cofactor and without the use of reagents for regenerating the cofactor. Although the process shown here is not economically practical, it may be a harbinger of useful and technically feasible chemical reaction systems based on immobilized enzymes requiring cofactors.
Dispersions in hydrocarbon fermentation. A retrospective study
Authors: Bajpai R. K. , Prokop A. , Ramkrishna D.
Published: December 2004

A nondimensionalized plot, obtained by normalizing the drop‐size distribution in the hydrocarbon phase using the Sauter mean diameter, shows a tendency towards self‐preservation of the distribution. Changes of distribution in time during the course of fermentation, initial dispersed phase fraction, speed of rotation, and reactor size were taken into account. Using this self‐preserving property, an empirical (single parameter) equation has been proposed for drop‐size distribution. Data, available from the literature, are presented for non‐biological and biological systems (gas‐oil, n‐hexadecane, and n‐hexadecane dissolved in dewaxed gas oil as dispersed phases). The parameter, Sauter mean diameter, has been correlated with the operating conditions, and a critical review presented. Cell density was found to have significant effect on Sauter mean diameter. This effect has also been empirically explained. The possibilities of using generalized distribution in predicting the performance of fermenters is outlined.
Design of a large‐scale mammalian cell, suspension culture facility
Authors: Lynn J. Daniel , Acton Ronald T.
Published: December 2004

The design of a suspension culture facility capable of producing approximately 1012 cells per week has been developed on a small‐scale system which has evolved from various architectural, engineering, biological, and biohazard considerations. The smaller system is composed of spinner flasks (50 ml to 8 liters) modified for semicontinuous culture conditions, metal reservoirs, a continuous flow centrifuge, and supportive equipment. The large system which is under construction is composed of metallic vessels of up to 500 liter working volume with hard plumbing, monitors, controllers, recorders, continuous flow centrifuge and other ancillary equipment. This system begins with medium preparation and ends with harvesting of cells and disposition of supernatant. The design of this turn‐key operation was developed over a two and one‐half year period through the cooperation of private industry, the federal government, and the academic community.
Rapid measurement of monod half‐velocity coefficients for bacterial kinetics
Authors: Williamson Kenneth J. , McCarty Perry L.
Published: December 2004

The common methods for measuring Monod half‐velocity coefficients are reviewed. All methods have serious disadvantages for obtaining rapid and accurate measurements whether batch‐fed or continuous‐fed systems are used. An “infinite dilution” technique is described that overcomes these difficulties. Data obtained by this method for autotrophic oxidation of NO2− and NH4+gave 20°C, pH 7.0, K3 values of 0.07 mg NO2−‐N/liter and 0.50 mg NH4±N/liter, respectively.
The transient response to pH and temperature shock loading of fermentation systems
Authors: Gaudy A. F.
Published: December 2004

Recent findings in the author's laboratories relative to the determination of the mode of response of continuously cultured heterogeneous populations to step changes in pH and in temperature are reviewed and discussed in light of possible effects of specific growth rate, μ, on the severity of substrate leakage in the effluent during the transient phase.
Thermophilic Anaerobic Digestion of Solid Waste for Fuel Gas Production
Authors: Cooney Charles L. , Wise Donald L.
Published: December 2004

Anaerobic digestion offers a potential means of converting organic solid waste into fuel gas and thereby provide a supplemental and readily utilizable source of energy. We are particularly interested in the use of thermophilic digestion over a mesophilic operation for it can achieve higher rates of digestion, greater conversion of waste organics to gas, faster solid–liquid separation, and minimization of bacterial and viral pathogen accumulation. Our results comparing mesophilic (37°C) and thermophilic (65°C) anaerobic digestion of domestic solid waste confirm the increased rate and conversion of waste to methane. In addition, utilizing radioactive labeling of glucose and acetic acid, we have measured the volumetric rates of volatile acid production and disappearance under both mesophilic and thermophilic conditions.
Wine fermentations using membrane processed hydrolyzed whey
Authors: Roland J. F. , Alm W. L.
Published: December 2004

A process for the utilization of modified whey syrups in wine alcohol fermentations is described. Palatable wines containing 10–12.5% alcohol were produced when various strains of S. cerevisiae var. ellipsoideus were fermented with hydrolyzed whey permeate syrups and grape juice concentrates. Experimental control of final alcohol and residual sugar levels in the wines by various chaptalization techniques is discussed. The possibility of utilizing this process in areas where both whey and grapes are abundant is mentioned.
Stimulation by organic solvents and detergents of conversion of L‐sorbose to L‐sorbosone by Gluconobacter melanogenus IFO 3293
Authors: Martin C. K. A. , Perlman D.
Published: December 2004

Treatment of Gluconobacter melanogenus IFO 3293 cells with benzene, carbon tetrachloride, cyclohexane, deoxycholate, toluene, or xylene stimulated their conversion of L‐sorbose to L‐sorbosone two‐ to threefold. The degree of stimulation depended upon the length of exposure time to the agent and the age of the G. melanogenus cells. A rapid decrease in viability of the cells and degradation of cell RNA was noted after treatment with the effective agents. The G. melanogenus cells were unable to absorb L‐sorbose actively after toluene treatment.
Enzyme immobilized in a packed‐bed reactor: Kinetic parameters and mass transfer effects
Authors: Marrazzo W. N. , Merson R. L. , McCoy B. J.
Published: December 2004

To describe axial dispersion, particle film mass transfer, intraparticle diffusion, and the chemical reaction of the substrate for enzymes immobilized in porous particles in packed columns, we have developed mathematical models for first‐ and zero‐order limits of Michaelis‐Menten kinetics. Steady‐state solutions were derived for both long and short column boundary conditions and for plug flow. Theory was compared to experiments of hydrolysis of sucrose catalyzed by invertase bound to porous glass particles. Steady‐state conversions were measured for a range of flow rates. Pulse response experiments with inert packing were used to determine values of bed void fraction and particle porosity.
Extended Monod equation for batch cultures with multiple exponential phases
Authors: Tsao George T. , Hanson Thor P.
Published: December 2004

The batch growth curves of Laclobacillus delbreuckii exhibit several exponential phases. From the results of a series of shaker flask experiments, the position of the slope changes in the growth curve and the overall bacterial yield is affected by the initial amount of yeast extract in the medium. It is postulated that this behavior is due to several growth enhancing substances that are initially in the yeast extract and are consumed by the bacteria during the course of the fermentation. Using a Monod‐type expression to represent the effect of growth enhancing components in a proposed growth rate expression, a mathematical model of the system is set up and solved on the analog computer.
Reversal of enzymatic hydrolysis: Rate and extent of ester synthesis as catalyzed by chymotrypsin and subtilisin Carlsberg at low water concentrations
Authors: Ingalls Robert G. , Squires Robert G. , Butler Larry G.
Published: December 2004

Immobilized chymotrypsin catalyzes esterification of N‐acetyltyrosine in a medium containing high concentrations of alcohols. The hydrophilic support and inclusion of glycerol protect the enzyme activity and allow catalysis to proceed in the presence of only 10% (v/v) water. The same equilibrium concentration of ester is obtained whether reaction proceeds from ester or from free acid. Hates of ester synthesis and hydrolysis are similar when measured under the same conditions, but are at least one order of magnitude slower than optimal rates of hydrolysis. Subtilisin Carlsberg in the free, unmodified form catalyzes ester synthesis at even lower water concentrations; optimal rates are obtained at 5–15% H2O.

Hydrolytic enzymes can thus be utilized as catalysts of synthesis reactions in nonaqueous solvents where synthesis is thermodynamically favored over hydrolysis; in some cases this may provide economic and/or energetic advantages over conventional techniques.
Thermophilic microbiological treatment of high strength wastewaters with simultaneous recovery of single cell protein
Authors: Surucu G. A. , Engelbrecht R. S. , Chian E. S. K.
Published: December 2004

Simultaneous removal of organic materials and recovery of protein in the form of bacterial cells from a simulated high strength biodegradable wastewater was studied using thermophilic aerobic microorganisms. A naturally occurring mixed culture of thermophilic microorganisms was obtained from soil, wastewater, hay, silage, etc. A chemically defined medium containing glucose along with other essential nutrients was employed as the feed. The kinetic behavior of the culture was studied in a continuous culture at an optimum temperature of 58°C. Studies were also performed on the effects of solids retention time (SRT) on the observed cell yield and the protein and ash content of the harvested biomass. An economic analysis of the process or single cell protein recovery was given.
The yields of extracted protein and of residual fiber from potato haulm taken as a by‐product
Authors: Carruthers I. B. , Pirie N. W.
Published: December 2004

In July the yield of protein extractable from potato haulm could be 600 kg/ha and the beginning of September it is 200 kg/ha. The yield of fiber containing 1 to 2% N is less affected by maturity. The annual waste of extractable protein, suitable for feeding nonruminants, is about 60,000 tons. The contribution that some small changes in conventional potato husbandry might make to minimizing this waste is discussed.
Investigation of the unit operations involved in the continuous flow isolation of β‐galactosidase from Escherichia coli
Authors: Higgins J. J. , Lewis D. J. , Daly W. H. , Mosqueira F. G. , Dunnill P. , Lilly M. D.
Published: December 2004

A 1000 liter fermentor has been used to produce a continuous feed of Escherichia coli containing a high level of β‐galactosidase. We have investigated the individual unit operations for the isolation of the enzyme: cell disruption, nucleic acid removal, protein precipitation, and solid–liquid separation after each stage. Using the information obtained we have been able to operate a semicontinuous process which when fully continuous would yield 100 g protein/hr, comprising 23% β‐galactosidase.
Rate of catalytic oxidation and decomposition of NADH by graphite in aqueous solutions
Authors: Wallace Thomas C. , Coughlin Robert W.
Published: December 2004

Graphites of different manufacture and origin exert positive but different accelerations on the rate of oxidation of NADH to NAD+ in aqueous solution; different proportions of the oxidized form of NAD retain enzymatic activity depending on the nature of the graphite. Oxidative pretreatment of the graphite surfaces increases the rates of NADH oxidation, but subsequent silanization of the surfaces to attach alkylamine groups causes the rates to decrease. The experimental results suggest the presence of at least two types of sites on graphite surfaces: One very reactive site which produces a high percentage of an enzymatically inactive reaction product of NADH and is itself deactivated during the course of reaction, and another type of site which promotes the oxidation of NADH to enzymatically active NAD+ in high yields.
Distribution of dispersed oil phase in hydrocarbon fermentations
Authors: Ho Chester S. , Erickson Larry E.
Published: December 2004

Recent experimental results show that the spreading coefficient frequently becomes positive when Candida lipolytica is cultivated on n‐hexadecane. The effects of oil spreading at the surface of air bubbles in an airlift fermentor are examined using a mathematical model. The distribution of the oil phase with position and among the phases is determined using computer simulation. The simulation results qualitatively explain some of the experimental observations which have been previously reported.
Oil drop size and gas hold‐up in an oil–water airlift system with motionless mixers
Authors: Gutierrez J. R. , Erickson L. E.
Published: December 2004

The degree of emulsification, measured as surface area of oil generated, was studied. The effect of interfacial tension, volume fraction of oil, and power per unit volume on the Sauter mean diameter of the oil drops was determined in an airlift system with motionless mixers. A mathematical expression to predict the Sauter mean diameter was developed using regression techniques. From this equation another equation, which will predict the surface area of oil in terms of the same variables, was derived. The effects of water air surface tension and power per unit volume on the gas hold‐up were obtained using similar techniques. The results show that the interfacial tension and the surface tension are important variables when hydrocarbon fermentations are carried out in airlift systems.
Mixing, mass transfer, and scale‐up of polysaccharide fermentations
Authors: Margaritis Argyrios , Zajic James E.
Published: December 2004

Microbial polysaccharides are rapidly emerging as a new and important source of polymeric materials. These biopolymers have novel and unique properties and already have found a wide range of applications in the food, pharmaceutical, and other industries. In view of the impending importance of polysaccharides as an industrial commodity, there is renewed interest in the area of product and process development. This paper summarizes the state‐of‐the art in polysaccharide fermentations. An attempt is being made to review the following areas: rheological characteristics of polysaccharide solutions, mixing and power requirements of polysaccharides and other highly viscous non‐Newtonian systems, oxygen mass transfer, and scale‐up problems encountered in polysaccharide fermentations.
Alkali treatment and fermentation of straw for animal feed
Authors: Han Y. W. , Yu P. L. , Smith S. K.
Published: December 2004

The feed value of annual ryegrass straw was improved by treatment with various concentrations of NaOH or NH3 followed by fermentation of the treated straw with a mixed culture of Cellulomonas sp. and Alcaligenes faecalis. Laboratory feeding trials with voles showed that NaOH or NH3 treatment considerably increased the feed efficiency of straw, but apparently gave a poorly palatable product. Fermentation tended to decrease the in vitro rumen digestibility (IVRD) of alkali‐treated straw. The fermentations were carried out aerobically on a semisolid straw matrix having 11–86% moisture. Treatment by both NaOH and NH3 increased the IVRD of straw. NH3 also increased the nitrogen content in straw. The optimum condition for alkaline treatment of the straw was 4–6% NaOH for 1 hr or with 3% NH3 for four weeks at room temperature. A minimum of 63% moisture was needed for significant fermentation of the straw. The combined effects of NaOH treatment and fermentation more than doubled crude protein, doubled crude fat, and increased IVRD by 75%. The NH3 plus fermentation treatment tripled crude protein, doubled crude fat, and increased IVRD by 60%. Acetic acid was the main volatile fatty acid in the fermented straw.
Solubilization of cheese whey protein by trypsin and a process to recover the active enzyme from the digest
Authors: Monti J. C. , Jost R.
Published: December 2004

Porcine trypsin (EC 3.4.4.4) converted, within approximately 2 hr at 50°C, its 1000‐fold weight of water‐insoluble, heat‐denaturated cheese whey protein into a water‐soluble product. In the course of this digestion, the enzyme increased the α‐amino nitrogen of the protein by a factor of >20, from 0.40 to 9.40%. After digesting the water‐insoluble whey protein, fully active trypsin could be recovered from the soluble digest with the aid of a cellulose‐based affinity adsorbent. The enzyme which was eluted from a column of p‐aminobenzamidine, bound to succinylated aminododecylcellulose, was fully active and showed essentially unchanged kinetic properties with a synthetic substrate, L‐benzoyl‐arginine p‐nitroanilide. It was possible to perform, with the same amount of trypsin, three subsequent and equally effective solubilizations of whey protein, followed by a fourth digestion which still yielded a soluble product, but was considerably slower and incomplete. During each digestion, an estimated 30% of the trypsin was lost. The was not due to a decreased efficiency of the affinity adsorbent, as its trypsin‐binding capacity was essentially unaffected after over 10 cycles of use.
Adsorption of cellulose by Trichoderma viride
Authors: Binder A. , Ghose T. K.
Published: December 2004

Adsorption of cellulase by Trichoderma viride QM 9414 has been studied with resting and growing cells and equations have been derived to describe the process quantitatively. It has been observed that the adsorption is a purely physical process being dependent only on cell and cellulose concentrations. It has also been demonstrated that adsorption isrequired for the induction of cellulases; some discussions are devoted to this point.
Toxic effects of fatty acids on yeast cells: Possible mechanisms of action
Authors: Huňková Z. , Fencl A.
Published: December 2004

As shown in a previous paper, threshold concentrations of lower and intermediate fatty acids inhibit the uptake of inorganic phosphate, growth, and cell division in yeast cells, This paper demonstrates that, apart from these effects, the acids cause an increase in the respiration quotient (RQ), inhibition of CO2 fixation, production of ethanol at the expense of anabolic processes, and inhibition of active amino acid transport in the yeast Candida utilis. On the other hand, the threshold concentrations have no effect on intracellular pH. The inhibition of the inorganic phosphate uptake cannot be the sole primary mode of action of fatty acids since the omission of inorganic phosphate in the incubation medium brings about an inhibition of anabolic processes that is lower than that brought about by fatty acids at concentrations still permitting some phosphate uptake, Although 2,4‐dinitrophenol and caproic acid at low concentrations cause an analogous decrease in biomass yield, their combination does not bring about any marked increase in the effect. Considering the physicochemical properties of fatty acids and their preferential action on energy‐requiring processes, one of the key sitesof action can be assumed to be the mitochondrial membrane. Fatty acids might inhibit the transport of anions, especially phosphate, across the membrane, and disturb the membrane potential by affecting the transport protons. The physicochemical properties of fatty acids may also give rise to their binding to other intracellular membranes and to a subsequent interference with the function of the corresponding organelles.
Potentiometric determination of coenzyme‐dependent oxidoreductase enzymes with recycling of the coenzyme
Authors: Wallace Thomas C. , Coughlin Robert W.
Published: December 2004

By enzymatically establishing a rapid (essentially equilibrium) coupling of a redox coenzyme such as NAD with the components of the ferrocyanide–ferricyanide half‐cell (e.g., using excess diaphorase) the half‐cell potential can be used to monitor another enzymatic reaction involving the same coenzyme. This approach provides a general, rapid potentiometric method of assaying coenzyme‐dependent oxidoreductase enzymes. We show that these assay systems can be designed for multiple turnover of coenzyme (in our case NAD) during a single assay thereby amplifying the rate of electromotive force (emf) change with a concomitant increase in sensitivity of enzyme assay. This allows the use of small concentrations of coenzyme and extension of the range of enzyme concentrations that may be assayed.