bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement of yeast concentrations in liquid hydrocarbon fermentations: Influence of experimental conditions and statistical significance of the results obtained
Authors: Concone Bruno R. V. , Hiss Haroldo , Pilar Maria Del , Paz G. , Patricio Carolina G. , Borzani Walter 
Published: December 2004

AbstractThe influence of the following factors on the measurement of yeast concentration in liquid hydrocarbon fermentations was studied: surfactant, type (Tween 20, Tween 80, and G 3300), yeast concentration (0.215 to 0.272 and 3.37 to 4.08 g/liter, as dry matter), oil concentration (8.32 and 61.6 g/liter), surfactant, concentration (0.515, 1.030, 1.545, and 2.060 g/liter), and time of contact of the surfactant with the oil‐yeast‐aqueous medium mixture (2 and 10 min). The statistical significance of the obtained results was determined.
Proteolytic components of alkaline proteases of Bacillus strains. Zymograms and electrophoretic isolation
Authors: Zuidweg M. H. J. , Bos C. J. K. , Van Welzen H. 
Published: December 2004

AbstractCharacterization of proteolytic activity in preparations or fermentation broth is accomplished by methods based on a combination of disc electrophoresis and visualization of the activity. The methods permit a direct, comparison with reference preparations. All alkaline proteases studied, including the three subtilisins, were found to consist of several proteolytic components. The zymograms of the subtilisin type preparations show an irregular pattern. At least 14 different components may be observed, belonging to 6 types of mobility pattern, 3 of which could be assigned to the subtilisins. None of the components belongs to the group of metalloproteases. A quite regular pattern is shown by the zymogram of protease preparations produced by the alkalophilic Bacillus strains.A few of the components of the subtilisin preparations Maxatase and protease A were isolated by preparative disc electrophoresis and by disc electrofococusing, allowing a further characterization. Special attention was directed to the determination of properties specific for the application of subtilisins as additives in household detergents. Thermostability in sodium tripolyhosphate solution was found to range from about 10% for one of the minor components to 80% for the main component of Maxatase. Three types of curves representing the effect of pH on the activity were observed. The curve of the main component of Maxatase shows a characteristic shape with a maximum at pH 10.3: with other components lower pH optima were observed. Isoelectric points of the component were found to range from pH 7 to 10.
Pilot plant conversion of steroid using resting cell suspension as biocatalyst
Authors: McGregor W. C. , Tabenkin B. , Jenkins E. , Epps R. 
Published: December 2004

AbstractResting cell suspensions of Sepedonium ampullosporum have been used successfully in the pilot plant, transformation of 9β 10α‐pregna‐4, 6‐dien‐3, 20‐dione to its 16α‐hydroxy derivative. The resting cell enzyme system acted as a stable respiratory unit up to 150 hr after resuspension in water. Semicontinuous addition of substrate to the same cell suspension reduced overall conversion lime by 67%.Aeration and agitation were important factors affecting conversion rates. The hydroxylating system had a critical oxygen concentration above 90% saturation of air in water. Hydroxylase activity was inhibited by cyanide an d totally inhibited by the respiratory inhibitor antimycin A at concentrations much less that that concentration required to block normal respiration.
Open tubular heterogeneous enzyme reactors: Preparation and kinetic behavior
Authors: Horvath Csaba , Solomon Barry A. 
Published: December 2004

AbstractTubes with immobilized enzymes on the inner wall, called open tubular heterogeneous enzyme reactors, were prepared by binding enzymes either directly to the tube inside surface or to a layer of a porous matrix attached to the inner wall. Kinetic studies of the hydrolysis of N‐benzoyl‐L‐arginine ethylester as a model reaction indicated that the reaction was kinetically controlled in reactors with surface bound trypsin and the kinetic parameters were evaluated by conventional methods. On the other hand, substrate diffusion in both the porous matrix and the bulk substrate solution strongly affected the rate of reaction in porous layer trypsin reactors. The highest overall rates of reaction were obtained when the reaction was bulk diffusion controlled and the measured rates were in agreement with those calculated from expressions derived from heat transfer theory. The design of reactors for the limiting cases of kinetic and bulk diffusion controlled reaction as well as a method for the determination of substrate diffusivity are outlined.
Immobilization of glucose oxidate on nickel‐silica alumina
Authors: Herring W. M. , Laurence R. L. , Kittrell J. R. 
Published: December 2004

AbstractThe preparation of a water‐insoluble derivative of glucose oxidase by covalent coupling to nickel on silica alumina is described. The catalyst has superior physical characteristics to conventional immobilized enzymes; although its activity and stability are now comparable to conventional catalysts, potential for significant further improvements has been demonstrated.
Film and pore diffusion studies with immobilized glucose oxidase
Authors: Rovito B. J. , Kittrell J. R. 
Published: December 2004

AbstractQuantitative studies are reported of external film and internal pore diffusion effects for glucose oxidase immobilized on porous glass in a continuous, tubular, packed bed reactor. The McCune and Wilhelm model for external film diffusion is shown to describe these data over a particle Reynolds number range from 0.2 to 25. The Thiele analysis provides a good description of internal pore diffusion resistances. It appears that immobilized enzymes free of internal diffusional restrictions generally require the use of supports with pore sizes larger than those currently available in porous glass.
Enzymatic solubilization of an insoluble substrate, fish protein concentrate: Process and kinetic considerations
Authors: Archer Michael C. , Ragnarsson Jon O. , Tannenbaum Steven R. , Wang Daniel I. C. 
Published: December 2004

AbstractThe solubilization of fish protein concentrate (FPC) by Bacillus subtilis protease (Monzyme) has been investigated. Conditions have been defined which eliminate the problems of microbial contamination and salt accumulation. A Kinetic treatment revealed that enzyme is adsorbed to the surface of the substrate, exposed to aqueous phase. The overall kinetics were described by a sequence of two first‐order processes—an initial, fast reaction in which loosely bound polypeptide chains are cleaved from an insoluble protein particle, and a second, slower reaction in which more compacted core protein is digested.
Selective substrate utilization by marine hydrocarbonoclastic bacteria
Authors: Soli Giorgio , Bens E. M. 
Published: December 2004

AbstractSeveral strains of bacteria, isolated from marine environments, were characterized for their hydrocarbon oxidizing abilities using a complex synthetic mixture of hydrocarbons. Attempts were made at a broad classification of these organisms on the basis of their behavior towards four major groups of hydrocarbons, normal paraffins, iso‐paraffins, cyclo‐paraffins, and aromatics, known to be present in crude oils. Although bacteria appear to be able to oxidize hydrocarbons at random, this study has shown that it may be possible to recognize a rudimental pattern if we view their oxidative abilities in terms of groups of hydrocarbons rather than individual compounds. A study of the action of combined strains on the synthetic hydrocarbon mixture was performed. It was found that no particular benefit could be derived as compared to the use of single strains.
Development of a recovery process for novobiocin
Authors: Belter P. A. , Cunningham F. L. , Chen J. W. 
Published: December 2004

AbstractA periodic countercurrent whole beer process was developed for the recovery of novobiocin to eliminate the high cost of mycelium filtration and accompanying antibiotic losses in the filter cake. In such a process screened, but unfiltered, novobiocin fermentation beer is contacted with a special grade of an anionic‐exchange resin in a series of specially designed, well mixed columns. Each column is fitted with a screen sized to retain resin within the column but allow the cells to press. Periodically the lead column is isolated from the column train, washed free of beer solids, and eluted. A freshly eluted column is placed in the trail position to allow countercurrent operation. The eluate is then processed to crystalline product.A mathematical model for the sorption of novobiocin was developed based on a suitable continuity equation and mass transfer and equilibrium relationships determined in the laboratory. Digital computations of this model correlated well with laboratory and pilot plant data, and predicted well the performance of the production units. This simulation has been in continued use to predict and reoptimize plant operation as process changes (such as improved beer titers, increased production rate, and the evaluation of superior ion‐exchange resins) occurred or were anticipated.
Methionine control of cephalosporin C formation
Authors: Drew Stephen W. , Demain Arnold L. 
Published: December 2004

AbstractDL‐Norleucine, a nonsulfur analogue of methionine was found to markedly stimulate synthesis of cephalosporin C by Cephalosporium acremonium strain CW19 in three different chemically defined media. Methionine, but not norleucine, stimulated cephalosporin C biosynthesis in a crude medium. The lack of stimulation by norleucine in complex medium was shown to be due to lack of uptake of this amino acid by mycelia growing in such a medium. In defined media containing a suboptimal methionine concentration, norleucine stimulated antibiotic production up to the level reached by optimal methionine. At an optimal dose of methionine, norleucine elicited no further increase in cephalosporin C production, indicating that these two amino acids act by the same mechanism. The data strongly indicate that stimulation by methionine is not a function of its ability to donate sulfur for antibiotic formation. Methionine was found to neither repress nor inhibit cysteine metabolism.
Accumulation of 5′ guanine nucleotides by mutants of Brevibacterium ammoniagenes
Authors: Furuya Akira , Okachi Ryo , Takayama Kenichiro , Abe Shigeo 
Published: December 2004

Abstract5′Xanthylic acid was efficiently converted to 5′guanine nucleotides (5′GMP, 5′GDP, and 5′GTP) without being degraded to guanine via 5′GMP by decoyinine resistant mutants of strain KY 13315 which had been isolated from Brevibacterium ammoniagenes and was practically devoid of 5′nucleotide degrading activity. The concentration of phosphate in the medium showed a profound effect on the ratio of the accumulated 5′guanine nucleotides, making it possible to direct the fermentation towards 5′GMP or 5′GTP. A direct accumulation of 5′guanine nucleotides from carbohydrate was possible by mixed cultivation of a 5′XMP accumulating strain and a 5′XMP converting mutant. A maximum concentration of 9.67 mg of 5′guanine nucleotides per ml was obtained directly from glucose in such a mixed culture.
Mixed culture biooxidation of phenol. III. Existence of multiple steady states in continuous culture with wall growth
Authors: Pawlowsky U. , Howell J. A. , Chi C. T. 
Published: December 2004

AbstractIt is shown that two steady states exist in certain regions of operation of a 2‐liter continuous stirred tank biological reactor. Transition was made from one steady state to another by applying shock loads of either phenol substrate which is inhibitory to the culture at high concentrations or by adding large additional amounts of concentrated organisms. The existence of the multiple steady states is ascribed to the existence of wall growth, and their position is determined by the amount of wall growth. Transient behavior of the system did not follow the predictions of the simple wall growth model but the culture appeared to undergo a lag period immediately after applying the shock load to the system. It is concluded that the stability of a continuous culture utilizing an inhibitory substrate is improved by increasing the degree of wall growth and decreasing the substrate feed concentration. It is also concluded that small scale experiments can usually not be interpreted correctly unless the effect of wall growth is taken into account.
Large scale production of bacteriophage Φ × 174
Authors: Siquet‐Descans F. , Calberg‐Bacq C. M. , Delcambe L. 
Published: December 2004

AbstractBacteriophage Φ × 174 was produced in 20 and 200 liter fermentors. The phage was concentrated without any loss of infectivity by precipitation with 10% (w/v) Poly(ethylene glycol) 6000 in 0.5M NaCl. The total yield of a 100 liter culture is around 1016 infectious particles. The final purification step in a CsCl gradient results in a 60 to 80% inactivation.
Activity and specificity of covalently immobolized wheat germ agglutinin toward cell surfaces
Authors: Zabriskie Dane , Ollis David F. , Burger Max M. 
Published: December 2004

AbstractWheat germ agglutinin protein, which is able to agglutinate tumor cells better than normal cells, was covalently bound to polyacrylamide gel beads. The specific binding activity of the protein was preserved on these beads and was expressed heterogeneously by the binding of mouse leukemia cells (L1210) to the protein coupled gels. The selective activity of the immobilized protein was maximal when the number of sites available to covalently couple the protein was lowest. The application of this observation to the general field of covalent immobilization of proteins and enzymes may be of considerable utility.
Biological wastewater treatment model building fits and misfits
Authors: Boyle W. C. , Berthouex P. M. 
Published: December 2004

AbstractThe modeling of biological wastewater treatment processes has received much attention over the past ten years. Efforts are underway to develop a unified model for these processes which will greatly aid in the design and operation of wastewater treatment facilities. This paper presents a philosophical discussion of model building strategies augmented by a discussion of statistical problems associated with model parameter estimation and model discrimination. This discussion further illustrates with actual data, that goodness of fit is not a sufficient condition for model acceptance. Numerous rival models are examined to illustrate this point. In order to verify a model or to discriminate between rival models, they must be “Put in jeopardy.” If this attitude is not employed in model building efforts, important discrepancies in the proposed model may go undetected.
Development and application of the thin channel rectangular air lift mass transfer reactor to fermentation and waste‐water treatment systems
Authors: Gasner Larry L. 
Published: December 2004

AbstractThe consideration of fermentation principles in the treatment of industrial and sanitary waste waters leads to substantial process improvements. In particular, the rate of reaction can be improved by several fold by establishing the proper environmental conditions for microbial growth in a fermentation system. Recent work on the concentric cylinder air lift has shown it to be an economical fermentor with many advantages over conventional fermentors. An attempt to improve the economical performance of this system led to the development of the thin channel rectangular air lift fermentor. This was based upon a theoretical analysis of performance parameters. The analysis indicates decreased bubble coalescence, increased bubble entrainment, decreased power costs, increased mass transfer coefficients, and decrease capital costs. Experience using a prototype thin channel rectangular air lift system with sanitary and industrial waste‐water treatment systems has demonstrated exceptionally high rates of BOD removal at low operating and capital costs.
Effect of aeration intensity on the biochemical composition of baker's yeast. II. Activities of the oxidative enzymes
Authors: Oura Erkki 
Published: December 2004

AbstractWhen the effect of catabolite repression is eliminated Saccharomyces cerevisiae prefers an aerobic metabolism. The potential for completely aerobic catabolism exists even in circumstances where its action is limited by the oxygen available. When the oxygen absorption in the medium is adequate, yeast uses a solely oxidative metabolism for energy‐yielding reactions. The changes observed in the activity of malate dehydrogenase can be described as a function of two isoenzymes, both of which are affected by oxygen; the isoenzyme participating in the glyoxylate cycle shows variations in activity similar to that observed in isocitrate lyase. NAD‐linked glutamate dehydrogenase activity roughly follows that of malate dehydrogenase and isocitrate lyase; in cultivations with the same growth rate the NADP‐linked dehydrogenase is insensitive to the oxygen level. The cytochromes aa3, b, and c have a clear maximum at low oxygen tension, the most sensitive being cytochrome aa3. The imbalance between cytochrome c:oxygen oxidoreductase activity and the amount of cytochrome aa3, and the correlation observed between respiration rate and the activities of cytochrome c oxidase and NADH2:cytochroine c oxidoreductase are discussed. Methods used for estimation of cytochromes are compared.
Production of a new thermostable neutral α‐galactosidase from a strain of Bacillus stearothermophilus
Authors: Delente J. , Johnson J. H. , Kuo M. J. , O'Connor R. J. , Weeks L. E. 
Published: December 2004

AbstractAn intracellular, thermostable, neutral α‐galactosidase (α‐D‐galactoside galactohydrolase EC 3.2.1.32) was produced in pilot plant quantities from a strain of Bacillus stearothermophilus. The organism was cultured at 50°C in a soluble neutral medium containing water extract of soybean meal (3%) and 0.5% yeast extract. The enzyme biosynthesis was inducible and sensitive to catabolite repression. After autolysis of the cells, the α‐galactosidase was selectively and quantitatively complexed from clarified beer directly onto DEAE Sephadex; and enzyme‐rich fractions were batchwise eluted with an increasing gradient of NaCl solutions. The eluates were given two consecutive isopropyl alcohol precipitations, and the aqueous solutions of the second precipitate were dialyzed and lyophilized. Final product activity recovery was 72% based on the crude fermentation beer. Best specific activity was 5.2 u/mg protein. Further laboratory purification (DEAE Sephadex and Bio‐Gel P200) yielded a product with 14.2 u/mg protein.
Death kinetics of yeast in spray drying
Authors: Elizondo Hector , Labuza T. P. 
Published: December 2004

AbstractThe death kinetics of a strain of Saccharomyces cerevisiae were studied in an industrial scale spray drier. In solution studies, the death kinetics of yeast was found to be comparable to pathogen destruction. From the studies in drying of yeast a prediction of a 4 log cycle decrease in viable cells of pathogens could be made for normal processing conditions. This should insure the safety of spray‐dried foods unless after contamination occurs. It was found that during drying, although the rate of death is high, the activation energy is greatly decreased over that of death in aqueous solution (reduction from 130 kcal/mole to 5 kcal/mole). The reduction in Ea may be attributed to the thermodynamic compensation phenomenon in which the resulting negative entropy of reaction acts to protect the cells through a water–protein interaction. However, the possibility of a change in death mechanism cannot be precluded. Overall, these results suggest the danger in extrapolating death kinetics to high temperature.
Continuous culture of Thiobacillus ferrooxidans on a zinc sulfide concentrate
Authors: Gormely L. S. , Duncan D. W. , Branion R. M. R. , Pinder K. L. 
Published: December 2004

AbstractA zinc sulfide concentrate was leached microbiologically by Thiobacillus ferrooxidans in a continuous stirred tank reactor. A model was developed to predict, the leaching kinetics when the bacterial growth rate was not limited by any substrate other than the zinc concentrate, and it was modified to explain the observed results.Stable steady sates were obtained over a range of dilution rates from 0.0171 to 0.1038 hr−1. Because a solid substrate was used, the specific growth rate of the bacaeria was not a unique function of the subastrate concentration, and conventional contnuous culture theory based on the Monod equation did not apply to this system. The leaching rates and bacterial growth rates were first order in mineral surface area cocentration.
A rational approach for predicting the dissolved oxygen profile in receiving waters
Authors: Peil K. M. , Gaudy A. F. 
Published: December 2004

AbstractA practical method for predicting the dissolved oxygen (DO) profile in a stream receiving biodegradable waste is presented. In this method the BOD (accumulated O2 uptake) curve is obtained using an open jug technique. The accumulated O2 uptake curve thus developed is employed in numerical integration with the physical reaeration data for the receiving stream to predict the DO profile in the stream. In the present study, the method was examined using 10‐liter open jar reactors to obtain the O2 uptake curves, and the receiving stream was a 670‐liter simulated stream apparatus which has been employed in previous studies on stream reaeration. The method was found to provide a fairly good prediction of the actual dissolved oxygen profile observed in the receiving stream. The effect of the reaeration constant, K2 )agitation effect(, on the kinetics of O2 uptake was also investigated and it was found that increased agitation (higher K2 value) caused some increase in the accumulated oxygen uptake (BOD) curve with most of the increase coming after the so‐called “plateau” area in the O2 uptake curve, i.e., in the general case, after the low point along the DO sag curve.
Some experiments and analysis of a predator‐prey model: Interaction between Colpidium campylum and Alcaligenes faecalis in continuous and mixed culture
Authors: Sudo Ryuichi , Kobayashi Kobee , Aiba Shuichi 
Published: December 2004

AbstractFollowing previous work in which a mass and monoxenous culture of Vorticella microstoma had been successfully established (Water Res., 7, 615 lpar;1973) another species of Ciliata, Colpidium campylum was subjected to continuous cultivation using Alcaligenes faecalis as the sole bacterial food and asparagine as the limiting substrate. This work was primarily undertaken to reveal the interaction and biological oscillation between these two types of organisms which simulate theecological behavior of activated sludge.The fact that the bacteria tended to flocculate and/ or deflocculate depending on the protozoan populastion density was incorporated into the rate equations to account for the oscillation in individual population density of the predator‐prey system The mathematical approach presented earlier by canal and other workers forbiological oscillation used a homogeneously of the bacterial food wasoverelooked in the earlier publication.