bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assimilation of liquid hydrocarbon by microorganisms. I. Mechanism of hydrocarbon uptake
Authors: Miura Yoshiharu , Okazaki Mitsuo , Hamada Shin‐Ichiro , Murakawa Shin‐Ichi , Yugen Rieko 
Published: December 2004

AbstractThe uptake mechanism of liquid hydrocarbons of low solubility in water was investigated, using microorganisms with different affinities for liquid hydrocarbon. Microorganisms which could utilize hydrocarbon were much more adherent to hydrocarbon than those which could not. The adhesive force between Candida intermedia IFO 0761 and hydrocarbon was higher than that of Candida tropicalis ATCC 20336, though both could utilize hydrocarbon. The total hydrocarbon uptake from the drop and accommodation forms of hydrocarbons was much higher than that from dissolved hydrocarbon. The uptake rate of drop‐form hydrocarbon was nearly equal to that of accommodation‐form hydrocarbon for C. intermedia, but was lower for C. tropicalis which shows lower adhesion to hydrocarbon.
Ferrous iron oxidation and uranium extraction by Thiobacillus ferrooxidans
Authors: Guay Roger , Silver Marvin , Torma Arpad E. 
Published: December 2004

AbstractThe microbiological oxidation of ferrous iron in batch and continuous systems has been investigated in relation to uranium extraction from a low‐grade ore by Thiobacillus ferrooxidans. The influence of the parameters, agitation, and aeration on oxygen saturation concentration, rate of oxygen mass transfer, and rate of ferrous iron oxidation was demonstrated. The kinetic values, Vmax and K were determined using an adapted Monod equation for different dilution rates and initial concentrations of ferrous iron. The power requirements for initial leaching conditions were also calculated. Uranium extraction as high as 68% has been realized during nine days of treatment. Regrinding the leach residue and its subsequent leaching yielded 87% uranium solubilization.
Continuous manufacture of yogurt. II. Procedure and apparatus for continuous coagulation
Authors: Driessen F. M. , Ubbels J. , Stadhouders J. 
Published: December 2004

AbstractThe procedure and apparatus for the continuous coagulation of yogurt are described. The continuous coagulation takes place in a plug‐flow fermentor. Prefermented milk is brought into this fermentor with the help of a centrifugal distributor, which avoids any undesirable mixing of the prefermented milk with the acidifying milk. A special stirring plate allows a stirring treatment in the coagulation tank. By this procedure the acidity and the viscosity of the final yogurt can be controlled between certain limits. The organoleptic characteristics of the continuous manufactured yogurt are good.
Amperometric assay of coenzyme‐dependent oxidoreductase enzymes in a flow‐through cell
Authors: Wallace Thomas C. , Leh Melonia Berezny , Coughlin Robert W. 
Published: December 2004

AbstractWe have demonstrated that a simple electrochemical cell can serve as a detector of NADH concentration in a flow system thereby providing an assay technique for NADH dependent enzymes. When this is applied to NADH produced by enzymatic reaction, then a reproducible measure of enzyme activity is obtained. This method of enzyme activity assay is applicable to a number of oxidoreductase enzymes which employ NAD+ or NADP+ as coenzymes to achieve substrate modification. The presence of electroactive species in samples of human serum has proved a serious problem in the electrochemical analysis of serum activity. These species produce a large background anode current at the anode voltage appropriate for NADH oxidation. The presence of this high current limits the usefulness of amplification of the current output to detect small changes in NADH concentration.
Cellobiase from Trichoderma viride: Purification, properties, kinetics, and mechanism
Authors: Gong Cheng‐Shung , Ladisch Michael R. , Tsao George T. 
Published: December 2004

AbstractThree distinct cellobiase components were isolated from a commercial Trichoderma viride cellulase preparation by repeated chromatography on DEAE cellulose eluting by a salt gradient. The purified cellobiase preparations were evaluated for physical properties, kinetics, and mechanism. Results from this work include: (1) development of a one step enzyme purification procedure using DEAE‐cellulose; (2) isolation of three chromatographically distinct, yet kinetically similar, cellobiase fractions of molecular weight of ∼76,000; (3) determination of kinetics which shows that cellobiase hydrolyzes cellobiose by a noncompetitive mechanism and that the product, glucose, inhibits the enzyme, and (4) development of an equation, based on the mechanism of cellobiase action, which accurately predicts the time course of cellobiose hydrolysis over an eightfold range of substrate concentration and conversions of up to 90%. Based on the data presented in the paper, it is shown that product inhibition of cellobiase significantly retards the rate of cellobiose hydrolysis.
Corynecin (chloramphenicol analogs) fermentation studies: Selective production of Corynecin I by Corynebacterium hydrocarboclastus grown on acetate
Authors: Nakano Hirofumi , Tomita Fusao , Yamaguchi Ken , Nagashima Minoru , Suzuki Takeo 
Published: December 2004

AbstractCorynebacterium hydrocarboclastus KY 8835 grew in the acetate medium and accumulated 28mM Corynecins which was the highest production yield among the processes using various carbon sources. Selective production of Corynecin I (over 90% of all Corynecins), which had been desired for increase of the product yield, was achieved in this acetate medium. To keep the concentration of acetate, ammonium, and phosphate ions in the optimum range throughout the fermentation, a solution containing CH3COOH (50%), CH3COONH4 (9%), and KH2PO4(0.2%) was fed continuously to the culture medium as the pH controlling agent. The addition of KCl (1%) and NaCl (1%) to the medium at 12 hr after inoculation stimulated the production of Corynecins.
Alcohol production by selected yeast strains in lactase‐hydrolyzed acid whey
Authors: O'Leary V. S. , Green R. , Sullivan B. C. , Holsinger V. H. 
Published: December 2004

AbstractEthanol production by Kluyveromyces fragilis and Saccharomyces cerevisiae was studied using cottage cheese whey in which 80 to 90% of the lactose present had been prehydrolyzed to glucose and galactose. Complete fermentation of the sugar by K. fragilis required 120 hr at 30°C in lactase‐hydrolyzed whey compared to 72 hr in nonhydrolyzed whey. This effect was due to a diauxic fermentation pattern in lactase‐hydrolyzed whey with glucose being fermented before galactose. Ethanol yields of about 2% were obtained in both types of whey when K. fragilis was the organism used for fermentation. Saccharomyces cerevisiae produced alcohol from glucose more rapidly than K. fragilis, but galactose was fermented only when S. cerevisiae was pregrown on galactose. Slightly lower alcohol yields were obtained with S. cerevisiae, owing to the presence of some lactose in the whey which was not fermented by this organism. Although prehydrolysis of lactose in whey and whey fractions is advantageous in that microbial species unable to ferment lactose may be utilized, diauxie and galactose utilization problems must be considered.
Characteristics of unbuffered gel‐immobilized urease particles. I. Internal pH
Authors: Atkinson B. , Rott J. , Rousseau I. 
Published: December 2004

AbstractThe overall rate of reaction of a gel‐immobilized urease particle necessarily depends upon the hydrogen ion concentrations within the particle. When the particle is unbuffered, the internal hydrogen ion concentrations are a consequence of the local rates of reaction and the rate of egress of the products of hydrolysis. A simple apparatus has been devised which allows a fairly rapid determination of the hydrogen ion concentration in the center of a particle for any given size, enzyme concentration, substrate concentration, and external pH. The products of urea hydrolysis are self‐buffering in the region of pH 8.83 and for an external pH less than the self‐buffering pH, the pH within the particle is increased because of the reaction. When the external pH is greater than the self‐buffering pH, the converse occurs. The pH at the center of the particle approaches the self‐buffering pH with an increase in particle size and enzyme concentration. The external pH necessarily differs in effect when above or below the self‐buffering pH. An increase in the external substrate concentration has a limited effect, simply rendering the local rates of reaction to be of zero order. The center‐line pH and therefore all internal hydrogen ion concentrations depend upon the parameter \documentclass{article}\pagestyle{empty}\begin{document}$ L\sqrt {\rho _e} $\end{document} and the external pH. Differences between the external and center‐line pH values of the order of units are unexceptional. The implications of the internal pH profiles on the local and overall rates of reaction are explored.
Process engineering studies on immobilized trypsin using molecular sieves as carriers
Authors: Mukherjea R. N. , Bhattacharya P. , Ghosh B. K. , Taraphdar D. K. 
Published: December 2004

AbstractIn the present investigation molecular sieve has been found to be a suitable carrier for the immobilization of enzymes. From the present study it may be specifically found that trypsin and pappain can be immobilized by molecular sieve type 4A following a very simple technique. The immobilized enzyme can be used both in packed as well as in a continuous stirred tank reactor (CSTR).
Hydrocarbon uptake in hydrocarbon fermentations
Authors: Gutierrez J. R. , Erickson L. E. 
Published: December 2004

AbstractCandida lipolytica (strain ATCC 8662) was grown on a simple defined medium with n‐hexadecane as the main carbon Source under batch fermentation conditions. The relative importance of the cells growing in the aqueous phase on the overall kinetics was studied. The effect of interfacial tension, unoccupied interfacial area, and pseudosolubility on the specific growth was also studied. Results are presented and discussed here.
Concentration of antibiotics by reverse osmosis
Authors: Datta R. , Fries L. , Wildman G. T. 
Published: December 2004

AbstractReverse osmosis is shown to be a viable process for the concentration of highly labile antibiotic solutions. Mathematical n10deJs of antibiotic inactivation by chemical and biological contamination are proposed and correlated with experimental data. Procedures for obtaining high antibiotic recoveries are discussed.
Chemical procedures for enzyme immobilization on porous cellulose beads
Authors: Chen Li Fu , Tsao George T. 
Published: December 2004

AbstractIn a previous article, the method of preparation and the physical properties of porous (75 to 80% porosity) cellulose beads were described (Biotechnol. Bioeng., 18, 1057 (1976)). The present article reports that the chemical procedures employed for immobilizing enzymes on ordinary cellulose can be applied to the porous cellulose beads. The results showed more enzyme loading on the beads than ordinary cellulose. The choice of the procedures might also affect the mechanical strength of the cellulose beads.
Acid mine drainage treatment with rotating biological contactors
Authors: Olem Harvey , Unz Richard F. 
Published: December 2004

AbstractA pilot scale rotating biological contactor (RBC) was set up near a coal mine at Hollywood, Penn. to evaluate ferrous iron, Fe(II), oxidation. Acid drainage from this mine entered the treatment unit which consisted of four sets of plastic disks affixed to a rotating central shaft. As the disks rotated half immersed in the flowing mine water, iron‐oxidizing bacteria, presumed to be Thiobacillus ferrooxidans, colonized the disk surfaces with an average population of 70,000 cells/cm2 and mediated the transformation of Fe(II) to the less soluble ferric state, Fe(III). Kinetics of microbial Fe(II) oxidation were established during an eleven month period of continuous pilot operation and were found to follow a concentration dependent first order relationship. Operating at an optimum disk rotation rate and hydraulic loadings of 2.7 and 5.4 gal/day‐ft2 (0.11 and 0.22 m3/day‐m2) resulted in the oxidation of an average 240 mg/liter influent Fe(II) to produce effluent Fe(II) of 2 and mg/liter, respectively. The RBC appears potentially useful as a first step in the total treatment of acid mine drainage.
Water recycle in biomass production processes
Authors: Topiwala H. H. , Khosrovi B. 
Published: December 2004

AbstractVarious aspects of process water recycle in a continuous flow fermentation process are analyzed. Simple mass balance equations in terms of product and feed components for a single‐stage reactor producing biomass are developed. Constraints on the recycle ratio, imposed by the efficiency of the dewatering stage, are examined. The recycle analysis is extended using a kinetic growth model incorporating water soluble product formation and growth inhibition. The potential effect of recycle on substrate conversion and product accumulation is also examined and the concept of a critical recycle ratio in fermentation processes is developed.
Isolation of lysozyme on chitosan
Authors: Muzzarelli Riccardo A. A. , Barontini Gaetano , Rochetti Roberto 
Published: December 2004

AbstractLysozyme has been immobilized on chitosan, a polyaminosaccharide, without using any intermediate reagent. The best pH conditions for operating the chitosan columns have been determined and the best eluting agent was found to be a 2% solution of propylamine. The lysozyme activity was determined after reacting lysozyme with the product of glycolchitin and Remazol Brilliant Blue R. The recovery of lysozyme from chicken egg white yields lysozyme with 55% activity.
Pore dimensions for accumulating biomass. I. Microbes that reproduce by fission or by budding
Authors: Messing R. A. , Oppermann R. A. 
Published: December 2004

AbstractThe relationship between the dimensions of a microbe and the accumulation of that microbe in porous, inorganic structures has been determined. That relationship is dependent upon the cell dimensions, the mode of reproduction, and the pore diameter of the material. In order to achieve high accumulation of microbes that reproduce by fission, at least 70% of the pores of an inorganic carrier should have pore diameters in the range of one times the smallest major dimension through five times the largest major dimension of the cell. To achieve the highest accumulation of microbes that reproduce by budding, at least 70% of the pores should have pore diameters in the range of one times the smallest dimension of the cell and less than four times the largest cell dimension. These relationships were established by varying the physical parameters of the carriers as well as their chemical composition.
Oxygen‐transfer rates and efficiencies in one‐ and two‐stage airlift towers
Authors: Orazem M. E. , Erickson L. E. 
Published: December 2004

AbstractThe primary consideration in fermentor design is the supply of oxygen to the growing microorganisms. The oxygen‐transfer characteristics of a two‐stage splitcylinder airlift tower were compared to those of a similar single‐stage airlift tower of equal liquid volume using a sodium sulfite–air system. At superficial gas velocities, from 720 to 1200 cm/min, no difference in KLa was apparent. The KLa was significantly larger in the two‐stage tower for a gas velocity between 1200 and 2728 cm/min. At 2728 cm/min a KLa of 25.2 min−1 was achieved in the two‐stage system, and at 2262 cm/min the two‐stage tower had a 54% larger KLa than the single stage. A comparison of dispersion‐volume based KLa showed a 27% larger value at a gas velocity of 2262 cm/min. The performance ratios for the two‐stage tower were larger than those for the single‐stage tower at oxygen‐transfer rates greater than 180 mmol/liter hr. A comparison of the data with literature values is presented.
Start‐up of chemostat: Application of fed‐batch culture
Authors: Yamané Tsuneo , Sada Eizo , Takamatsu Takeichiro 
Published: December 2004

AbstractA time‐optimal strategy for start‐up of a chemostat has been established by applying Miele's extremization method based on Green's theorem. The start‐up time is always minimized by traveling along the uppermost boundary of the set of admissible domains on the (vx, μ) phase plane. The solutions are batch culture for monotone increasing growth kinetics and exponentially fed‐batch culture followed by batch culture for substrate‐inhibition kinetics. A time‐suboptimal start‐up strategy, exponentially fed‐batch culture operated the same μ as that of chemostate, is proposed as more feasible than and physiologically preferable to the time‐optimal strategies. The complete set of equations of operations necessary for performing each of the optimal and suboptimal start‐ups is formulated. Numerical comparisons on the basis of continuous operation giving maximum productivities of cell‐mass outputs show that differences in times required for start‐up between optimal and suboptimal strategies are small.
Analysis of fermentation processes using flow microflourometry: Single‐parameter observations of batch bacterial growth
Authors: Fazel‐Madjlessi Jila , Bailey J. E. 
Published: December 2004

AbstractThe laser flow microfluorometer (FMF) can determine the amounts of certain components in single cells at sample rates of several thousand cells per second. This technique has been employed to characterize Bacillus subtilis populations in batch fermentations with different inocula. Protein and distributions obtained by FMF analyses at different times during the batch have been decomposed using an optimized fit of summed subpopulation distributions. The results of these decomposition calculations, some of which have been approximately confirmed by independent microscopic observations, indicate cells relative numbers of single rods, cell chains, spores, and swollen rounded cells change dramatically during the entire fermentation including the stationary phase. The dynamics of these subpopulations may be related to secondary metabolite production.
Maximum cell productivity by repeated fed‐batch culture for constant yield case
Authors: Weigand W. A. 
Published: December 2004

AbstractOptimal operation of repeatedly fed‐batch was determined by the continuous maximum principle for the constant yield case. The objective of maximum cell productivity for a fixed cell concentration was achieved by finding the substrate feeding policy that minimized the processing time. Analytical criteria for the optimal filling policy show that an exponential policy is optimum when the specific growth rate has a maximum, and also that operation in the simple repeated batch mode is optimum when the specific growth rate is monotonic increasing. Comparisons between optimal repeated fed‐batch culture and other modes of operation were made for the case of substrate‐inhibited growth. Cell productivity by repeated fed‐batch exceeds both batch and continuous operation for the case of low residual substrate concentration.
Characteristics of mechanically disrupted bakers' yeast in relation to its separation in industrial centrifuges
Authors: Mosqueira F. G. , Higgins J. J. , Dunnill P. , Lilly M. D. 
Published: December 2004

AbstractThe viscosity, density, and sedimentation characteristics of suspensions of whole and mechanically disrupted yeast cells were measured. Mechanical disruption increases the suspension viscosity and its non‐Newtonian behavior. Experiments showed a good correlation between laboratory‐ and industrial‐scale centrifugation results.
Peptide synthesis enzymatically catalyzed in a biphasic system: Water–water–immiscible organic solvent
Authors: Semenov Anatole N. , Berezin Ilya V. , Martinek Karel 
Published: December 2004

AbstractSynthesis of a peptide bond is suggested to be enzymatically catalysed in a biphasic system “water–water‐immiscible organic solvent”. The pH dependence of the apparent equilibrium constant is studied for synthesis of N‐acetyl‐L‐tryptophanyl‐L‐leucine amide from N‐Acet‐Trp andL‐Leu‐NH2. The reaction was performed in the biphasic system ethyl acetate plus water [from 2 to 2% (v/v)] in the presence of α‐chymotrypsin. The suggested approach is preparative value: with the stoichiometric ratio of the reagents, [N‐Acet‐L‐Trp] = [L‐Leu‐NH2] = 2 × 10−3M, the yield is practically 100% (in water, with other conditions being the same, the yield is not over 01.%).
Cephalexin synthesis by partially purified and immobilized enzymes
Authors: Choi W. G. , Lee S. B. , Ryu Dewey D. Y. 
Published: December 2004

AbstractAn enzyme which catalyzes the synthesis of cephalexin fromD‐α phenylglycinemethylester (PGM) and 7‐amino‐3‐desacetoxy‐cephalosporanic acid (7‐ADCA) was prepared from Xanthomonas citri (IFO 3835) and partially purified 30‐fold by ammonium sulfate fractionation, DEAE‐cellulose, and Sepharose‐4B column chromatography. The Km values for 7‐ADCA, PGM, and cephalexin were determined as 11.1, 2.1, and 1.61 mM, respectively. The enzymatic cephalexin synthesis follows the reversible bi‐uni reaction kinetics. The equilibrium constant is influenced by the initial mole ratios of 7‐ADCA and PGM. The cephalexin hydrolysis is catalyzed by the same cephalexin synthesizing enzyme, but methanol does not participate in the hydrolytic reaction. The amount of enzyme in the reaction mixture affects the initial rate but does not influence the equilibrium product concentration. This cephalexin‐synthesizing enzyme was immobilized onto several adsorbents. Among these, Kaolin and bentonite showed a higher retention of enzyme activity and stability for reuse. The immobilized‐enzyme reaction kinetics were investigated and compared with those of the soluble enzyme. A rate expression for the enzymatic synthesis of cephalexin was derived. The results of computer simulation showed good agreement with the experimental results.
Bioengineering report: Fouling biofilm development: A process analysis
Authors: Characklis W. G. 
Published: December 2004

AbstractBiofilm development at a surface is the net result of several physical, chemical, and microbial processes including the following: (1)transport of dissolved and particulate matter from the bulk fluid to the surface; (2) firm microbial cell attachment to the surface; (3) microbial transformations (growth, reproduction, etc.) within the biofilm resulting in production of organic matter; (4) partial detachment of the biofilm due primarily to fluid shear stress. This report presents a framework for analyzing the interrelated processes contributing to biofilm development. Some of the available rate and composition data are presented so that the relative process rates can be compared.
Microbial transformation of racemic hydantoins to D‐amino acids
Authors: Olivieri R. , Fascetti E. , Angelini L. , Degen L. 
Published: December 2004

AbstractIt has been shown that resting cells of Agrobacterium radiobacter catalyze a sequence of two stereospecific hydrolytic reactions leading to the complete transformation of racemic hydantoins to D‐amino acids. This report describes some properties of this new biocatalyst and its potential application for the production of some D‐amino acids, which are used as intermediates in the preparation of semisynthetic penicillin and cephalosporins.
Continuous cultivation of fission yeast: Classical and flow microfluorometry observations
Authors: Agar David W. , Bailey James E. 
Published: December 2004

AbstractThe fission yeast Schizosaccharomyces pombe was grown in glucose‐limited medium in a steady‐state continuous flow reactor. Changes in mean cell protein and RNA contents with growth rate are consistent with earlier observations under different conditions. Flow microfluorometry measurements of the frequency functions of DNA at different dilution rates show changes in coordination of DNA synthesis and cell separation. Shifting from batch growth to small dilution rates results in unusual cell aggregation which leads to multiple steady states at identical operating conditions.