bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of a bioluminescence ATP assay in brewery wastewater treatment studies
Authors: Hysert D. W. , Knudsen F. B. , Morrison N. M. , van Gheluwe G. , Lom T. 
Published: December 2004

AbstractThe importance of having a rapid method for determining the viable biomass in activated‐sludge wastewater treatment plants (WWTP) for process control and development is well recognized. The firefly bioluminescence ATP assay has been proposed for this purpose. Such an assay using partially purified firefly luciferase and synthetic firefly luciferin for the bioluminescence reaction, a liquid scintillation counter in the out‐of‐coincidence mode as luminescence detector, and a sludge ATP extraction technique involving dimethyl sulfoxide at room temperature is described. Experiments with several pure bacteria cultures were done to demonstrate the feasibility of applying this assay to activated sludge to activated sludge WWTP investigation and control. The ATP content of samples taken from various points in a 350000 gal/day brewery activated‐sludge WWTP was monitored for 4.5 months. Good linear correlation between ATP and mixed‐liquor suspended solids, return sludge suspended solids, and effluent suspended solids were observed. Percentage viabilities of the various sludge samples were derived from the ATP results.
Urease bound to chitin with glutaraldehyde
Authors: Iyengar Leela , Rao A. V. S. Prabhakara 
Published: December 2004

AbstractThe enzyme (urease amidohydrolase, EC 3.5.1.5) prepared from Cajanus indicus, has been immobilized with glutaraldehyde‐treated chitin as the solid support. The immobilized enzyme was characterized by determining the pH profiles and optimum temperature. Effect of glutaraldehyde concentration on the binding of enzyme to chitin was studied. The storage stability of the chitin–urease system was determined.
Proteolytic denaturation and methods of improving the stability of glucose isomerase preparations
Authors: Adler David , Lim Henry , Cottle David , Emery Alden 
Published: December 2004

AbstractEvidence is provided in support of proteolytic denaturation of free and immobilized preparations of glucose isomerase from a Bacillus species. A number of methods to improve the stability with respect to proteolysis have been tested and their advantages as well as shortcomings are discussed. These methods include hollow‐fiber treatment, gel permeation, thermal treatment, and addition of protease inhibitors. The half‐life of the free and the cellulose acetate fiber‐entrapped preparations of glucose isomerase can be significantly improved. For example, the hollow‐fiber treatment can improve the half‐life by an order of magnitude.
Properties of penicillin amidase immobilized by copolymerization with acrylamide
Authors: Szewczuk Apolinary , Ziomek Edmund , Mordarski Marian , Siewiński Maciej , Wieczorek Jadwiga 
Published: December 2004

AbstractAn enzyme preparation in a spherical granule form was obtained by copolymerization of penicillin amidase (EC 3.5.1.11) (previously modified with maleic anhydride) and acrylamide via a crosslinking agent. As compared with the native enyme, immobilized amidase is more resistant to heating, has a lower affinity to benzylpenicillin, and is less inhibited by phenylacetate. Its substrate specificity and optimum pH remain unchanged.
Bubble flow in the downflow section of an airlift tower
Authors: Orazem M. E. , Fan L. T. , Erickson L. E. 
Published: December 2004

AbstractCharacterization of the two‐phase flow in the downflow section of the airlift tower is necessary for accurate modeling of the airlift tower. A Split‐cylinder airlift tower was investigated for superficial gas velocities ranging from 0.0683 to 0.3315 m/sec for an air–water system. Statistical cross‐covariance techniques were used to yield velocities, void fractions, and flow rates corresponding to upward and downward components of bubble flow in the downflow section of the airlift tower. From these results the fraction of incoming air entrained in the downflow section was determined as a function of superficial gas velocity and position.
Whole‐cell hollow‐fiber reactor: Effectiveness factors
Authors: Webster I. A. , Shuler M. L. , Rony P. R. 
Published: December 2004

AbstractAnalytical expressions, which allow the generation of effectiveness factor graphs for a reactor system employing immobilized whole cells a biocatalyst, are presented. In particular hollow‐fiber devices (such as dialysis or ultrafiltration units) are considered. Such devices are analogs to a shell‐and‐tube heat exchanger. Whole cells are entrapped on the shell side: a nutrient solution is circulated through the tubes, substrate diffuses from the tube side, across the fiber, and into the cell mass on the shell side, where it irreversibly reacts to form product. The product back‐diffuses into the circulating nutrient solution. The overall substrate mass‐transfer process is hypothesized to be either diffusion limited in the hollow‐fiber tube wall and/or the shell‐side cell suspension and/or reaction limited at the enzyme sites within the whole cells. The first‐ and zero‐order limits of the Michaelis‐Menten rate law are used in generating effectiveness factor expressions. The effectiveness factor is a function of reaction order, Thiele modulus, diffusion coefficient ratio (defined as the effective substrate diffusivity in the hollow‐fiber membrane wall divided by the effective substrate diffusivity in the cell suspension), partition coefficient, volume of the cell suspension, and hollow‐fiber width. Equations for the effectiveness factor are also detailed when the hollow‐fiber mass‐transfer resistance is far greater than the cell suspension mass‐transfer resistance. An effectiveness factor chart is presented specifically for the commercially available C‐DAK 4 dialyzer (Cordis Dow Co., Miami, Florida). In general terms the effectiveness factor expressions are applicable for characterizing diffusion and reaction within a catalytically active cylindrical annulus, Whose inner surface offers a diffusional resistance and whose outer surface is impermeable to reactants. Some generalization of the Thiele modulus is undertaken which serves to draw the asymptotes on the effectiveness factor charts together. Comment is made on the variation of the slope of the effectiveness factor graph and its relation to the change in the observed reaction activation energy. Possible application of the model to the catalytic tube wall reactor is discussed.
Production of aflatoxin in corn by a large‐scale solid‐substrate fermentation process
Authors: Silman R. W. , Conway H. F. , Anderson R. A. , Bagley E. B. 
Published: December 2004

AbstractCulturing of Aspergillus flavus was conducted in static flask cultures and 4 in. × 5 ft columns (containing 7–8 kg corn) to measure the effects of moisture, temperature, and air flow upon growth and the production of aflatoxin. Aflatoxin levels as high as 6200 ppb (dry basis) in 10 days were observed. Conditions were selected (ca. 20% moisture, 0.008 liter air/kg corn/min air flow with 1.5 liter/kg/min recirculated) for production of aflatoxin in 1200 bushels of corn in a 18‐ft diam corrugated steel Butler storage bin for preparation of contaminated corn for animal feeding trials and for testing of an ammoniation process for decontamination of aflatoxin in corn. A target level of 1000 ppb aflatoxin was attained.
Effect of interstage mixing in multistage culture systems on continuous biomass production
Authors: Páca Jan , Grégr Vratislav 
Published: December 2004

AbstractThe significance of the interstage mixing on important process parameters of biomass production was studied. The experiments were performed in a multistage tower fermentor and in fermentors in series. The interstage mixing effect can be evaluated under conditions of geometrical similarity, identity of oxygen transfer rate, and identity of dilution rate per stage in the individual stages of both culture systems. Candida utilis was cultivated on a synthetic medium with ethanol as the sole carbon and energy source in the concentration range 10–100 g/liter. Dilution rate, temperature, and pH in each stage of both culture systems were kept constant. It was demonstrated that in the multistage tower fermentor the definite backflow which ensures the permanent reinoculation by adapted cells significantly decreases the inhibitory effect of higher ethanol concentrations on the cell growth and on the rate of ethanol utilization.
Application of balancing methods in modeling the penicillin fermentation
Authors: Heijnen J. J. , Roels J. A. , Stouthamer A. H. 
Published: December 2004

AbstractThis paper shows the application of elementary balancing methods in combination with simple kinetic equations in the formulation of an unstructured model for the fed‐batch process for the production of penicillin. The rate of substrate uptake is modeled with a Monod‐type relationship. The specific penicillin production rate is assumed to be a function of growth rate. Hydrolysis of penicillin to penicilloic acid is assumed to be first order in penicillin. In simulations with the present model it is shown that the model, although assuming a strict relationship between specific growth rate and penicillin productivity, allows for the commonly observed lag phase in the penicillin concentration curve and the apparent separation between growth and production phase (idiophase–trophophase concept). Furthermore it is shown that the feed rate profile during fermentation is of vital importance in the realization of a high production rate throughout the duration of the fermentation. It is emphasized that the method of modeling presented may also prove rewarding for an analysis of fermentation processes other than the penicillin fermentation.
Hydrolysis of urea by gelatin‐immobilized urease: Separation of kinetic and diffusion phenomena in a model immobilized‐enzyme‐reactor system
Authors: Bollmeier John Philip , Middleman Stanley 
Published: December 2004

AbstractExperiments and appropriate mathematical models are presented in an attempt to elucidate and separate the effects of mass transfer and immobilization on the apparent kinetics of hydrolysis of urea by urease immobilized within a crosslinked gelatin film. Diffusion of urea through the gelatin matrix appears to exert the major influence on the observed kinetics. Diffusion coefficients are measured, and a model for the “effectiveness factor” is presented, accounting for this aspect of mass transfer control. A secondary, but significant, influence on apparent kinetics arises because the reaction products lead to an increased pH level which, because of diffusion resistance, remains high within the gelatin matrix. For pH levels in the 6.7 to 9.0 range the activity of urease is a strongly decreasing function of pH. An approximate model accounting for ionic equilibrium allows this pH–diffusion effect to be introduced in such a way as to lead to predictions of the apparent kinetics that are compared with experimental observations. Examination of these results indicates that the immobilization procedure leads to some loss of activity due to an interaction of the gelatin crosslinking reaction with the enzyme itself.
Preparation of immobilized phosphodiesterase from calf spleen and its use in oligonucleotide analysis
Authors: Seliger H. , Teufel E. H. , Philipp M. 
Published: December 2004

AbstractThe phosphodiesterase from calf spleen (EC 3.1.4.18) was immobilized on several supports. Some properties of the most suitable enzyme support system—calf spleen phosphodiesterase bound to agarose‐Concanavalin A—were investigated, e.g., pH dependence, influence of ionic strength of the buffer medium, and Zn2+‐ion inhibition. The immobilized spleen phosphodiesterase showed about 60% of the activity of the free enzyme: the activity toward several oligonucleotide test substrates was unchanged for two months.
Kinetics of microbial death by combined treatment with heat and antimicrobial agents
Authors: Tsuchido T. , Shibasaki I. 
Published: December 2004

AbstractStudies were made of the death kinetics of Escherichia coli cells heated at 46 to 56°C in 0.05M phosphate buffer (pH 7.0) containing either an amphoteric surfactant (Tego 15DL, 1–10 μg/ml) or sorbic acid (0.5 to 3%). A linear relationship was obtained on the Arrhenius plot for the death of cells heated with each antimicrobial agent. The kinetics of the action of the surfactant, however, differed from that of sorbic acid. With the amphoteric surfactant, the activation enthalpy of the death reaction decreased from 108 to 51 kcal/mol as the concentration of surfactant was increased in the range tested although the death rate remained high; whereas with sorbic acid the activation enthalpy remained fairly constant (104 ± 9 kcal/mol) independent of its concentration and the death rate was similarly high. Further, in the action of the amphoteric surfactant, a thermodynamic compensation effect was observed, the compensation temperature being 334°K (61°C), i.e., relatively close to the observed temperatures. For sorbic acid, however, this temperature seemed to be too high to observe when determined from the Arrhenius plot. The data of the dependency of the death‐rate constant upon the concentration of antimicrobial agent indicated a similar difference in the action of the two agents. Based on our results and on data obtained by other workers, we propose that antimicrobial agents that enhance cellular death induced by heating can be characterized into two types.
Dynamic aspects of radiorespirometry during the cell cycle of Candida utilis: Some observations in phased culture under carbon‐, nitrogen‐, and phosphorus‐limited growth
Authors: Dawson Peter S. S. , Steinhauer Lee P. 
Published: December 2004

AbstractMany changes that occur in a cell during the cell cycle can be demonstrated in synchronous cultures and can reveal dimensions of cell metabolism not attainable by the study of balanced growth of asynchronous populations in batch cultures or the steady state in chemostat cultures. The release of 14CO2 from specifically labeled glucose by phased (continuously synchronized) cultures follows a characteristic pattern (profile) that depends upon the stage in the cell cycle and the period of labeling used. Successive profiles throughout a cycle showed differences that were altered under different nutrient‐limiting growth conditions. Profiles obtained with glucose‐1‐14C, glucose‐2‐14C, glucose‐3,4‐14C, and glucose‐6‐14C and phased cells of Candida utilis under N‐, P‐, and C‐limited growth demonstrated the variable character of the metabolic activity that occurred in the cells while contour changes within the profiles across the cycle indicated possible correlations with activities of the hexose monophosphate, Embden‐Meyerhof‐Parnas, and tricarboxylic acid cycle pathways during the cell cycle. The basis of these changes and their use as elementary parameters for study of problems of physiological changes in vivo are considered.
Immobilization of β‐galactosidase, albumin, and γ‐globulin on epoxy‐activated acrylic beads
Authors: Hannibal‐Friedrich Otto , Chun Moonjin , Sernetz Manfred 
Published: December 2004

AbstractA comparative study was conducted into the immobilization of β‐galactosidase, albumin, and γ‐globulin on an epoxy‐activated polyacrylic matrix (oxirane C, Röhm‐Pharma GmbH, Darmstadt). The kinetic parameters of the immobilized β‐galactosidase were investigated with three kinds of miniaturized analytical reactors: namely, stirred batch, continuous stirred‐tank, and packed‐bed reactors. The optimum binding conditions, saturation activity and Michaelis constant of immobilized β‐galactosidase are given, together with determinations of the binding capacity of the oxirane C matrix for the three proteins investigated. For beta;‐galactosidase a saturation activity of 1300 U/g oxirane C was reached. The maximum binding, achieved by experiment, was 140 mg/g with 0.69 yield for albumin, 120 mg/g with 0.61 yield for γ‐globulin, and 40 mg/g with 0.42 yield for β‐galactosidase. From these data the inner surface of the matrix as a function of the size of the bound proteins was estimated.
Enzyme electrode for phenol
Authors: Kjellén Karin G. , Neujahr Halina Y. 
Published: December 2004

AbstractAn enzyme electrode is described for quantitative determination of phenol at micromolar concentrations. Immobilized phenol hydroxylase is attached to the surface of a Clark oxygen electrode. The Maximum rate of oxygen consumption is linearly dependent on phenol concentration over the 0.5–50μM range. The electrode can be used for at least 150 assays without an activity loss. Readout is very rapid—within 30 sec of sample addition. The electrode response is independent of pH between pH 6.5 and 9.5. The response increases linearly with temperature in the interval 10–40°C. It is necessary to incubate the enzyme electrode in a buffer containing NADPH for a few minutes before the addition of sample. This is to make the electrode response independent of the diffusion rate of this cosubstrate. This and other diffusional effects on the performance of the phenol electrode are discussed.
Stability of the Cellulase of Trichoderma reesei under use conditions
Authors: Reese Elwyn T. , Mandels Mary 
Published: December 2004

AbstractEnzyme stability studies have been reinvestigated under the conditions used for cellulose hydrolysis (pH 4.8, 50°C, 24 hr). The cellobiohydrolase (CBH) component as measured on Avicel is less stable than other enzymes of the cellulase complex, and is 60% inactivated by merthiolate (and other Hg compounds) under the above conditions. Endo‐β‐1,4‐glucanase is much more stable, and more resistant to merthiolate and other compounds. Under unshaken conditions the Avicelase of the Rutgers strain C 30 shows greater stability to heat than that of other available strains. Biocides must be selected not only for their ability to prevent contamination, but also for their compatibility with cellulases. Tetracycline and chlortetracycline are inexpensive, effective in very low concentrations, have no harmful effect on the enzymes, and are compatible with the yeasts that subsequently grow on the sugar solutions to produce alcohol. Attempts have been made to stabilize the enzymes by chemical modification in such a way as to maintain their solubility. Glutaraldehyde treatment greatly increased the enzyme size, lowered the pI values, and gave a slight shift in the pH activity curve. There was, unfortunately, no increase in enzyme stability, and the activity of enzymes on solid celluloses was adversely affected. Shaking greatly reduced the hydrolysis of Avicel by Trichoderma reesei C 30 enzyme. The adverse effect was accompanied by a decrease in recoverable enzyme and protein.
Growth and anthocyanin production by carrot suspension cultures grown under chemostat conditions with phosphate as the limiting nutrient
Authors: Dougall Donald K. , Weyrauch Keith W. 
Published: December 2004

AbstractChemostat cultures of carrot suspension cultures, where growth was limited by the concentration of phosphate in the input medium, were achieved by replacing a fixed proportion of the culture with fresh medium at daily intervals. In the range 0.05–0.30mM phosphate in the input medium and at a specific growth rate of 0.357 days−1, steady‐state culture density but not anthocyanin in the cells was strictly proportional to the input phosphate concentration with no intercept. At a phosphate concentration of 0.10mM and growth rates from 0.105 to 0.430 days−1, the steady‐state culture density could not be described by Monod's model of chemostat cultures, but could be described by Nyholm's model. The steady‐state levels of anthocyanin were not strictly proportional to the steady‐state biomass under all conditions, showing that anthocyanin production is not completely growth associated.
Growth energetics in the production of bacterial single cell protein from Methanol
Authors: Drozd J. W. , Wren S. J. 
Published: December 2004

AbstractBacteria grown on methanol exhibit a poor efficiency of energy conservation, which is mainly due to the low P/O ratio of 1 associated with methanol oxidation. Thermodynamic considerations indicate that a P/O ratio of at least 2 is possible for this step in substrate oxidation. This low efficiency of energy conservation is reflected in the yield values on methanol, which are very important in the consideration of biomass production from methanol. Unfortunately in continuous culture there is no obvious way to select for organisms with a greater efficiency of energy conservation.
Hydrophobic chromatography of β‐galactosidase
Authors: Chang C.‐T. , McCoy B. J. , Carbonell R. G. 
Published: December 2004

AbstractThe hydrophobic interaction of β‐galactosidase with Sepharose 4B substituted with 3,3′‐diaminodipropylamine was studied in both batch and column experiments. The equilibrium and the binding rate constants were determined for different phosphate buffer concentrations. The equilibrium constants exhibit a hysteresis effect, i.e., desorption constants are less than adsorption constants, and the higher the ionic strength to start the desorption, the larger the effect. The rate data are not satisfactorily described by a simple reversible first‐order model. The column chromatographic data are semiquantitatively described by a local equilibrium theory without axial dispersion or intraparticle diffusion.
Enzyme formation during solid‐substrate fermentation in rotating vessels
Authors: Silman Robert W. 
Published: December 2004

AbstractAspergillus awamori NRRL 4869 was cultured on the solid substrate, wheat bran, in a modified Rollacell apparatus to produce α‐galactosidase and invertase. The swivel cap on the elongated bottle permits the introduction of air while the bottle rotates. Parameters of air flow rate (0.05–0.2 liter/kg/min), rpm (0.15–15 rpm), and weight of solids (150 and 300 g) were varied. At low air flow rates (0.05 liter/kg solid/min), α‐galactosidase production was minimal independent of the rotation rate. At 0.15 rpm and 0.2 liter/kg solids/min air flow rate, invertase production ceased after five days; whereas α‐galactosidase production continued. The modified Rollacell can be a useful apparatus for studying solid‐substrate cultures.
Monolayer cultures of animal cells with the gyrogen equipped with tubes
Authors: Girard H. C. , Sütcü M. , Erdem H. , Gürhan I. 
Published: December 2004

AbstractThe gyrogen with tubes has been the object of repeated trials carried out over a period of some years. The aim of these trials was essentially to multiply BHK cells in monolayer and to reproduce the FMD virus in one operation. At the laboratory stage, the gyrogen represented three roller flasks; at the pilot stage, 100 roller flasks; and at the industrial stage, 500 flasks. Culturing cells on a glass support, is not in itself new, but the difficulty appeared when replicating the virus in order to obtain the high parameters necessary for vaccine production. Everything was accomplished so that finally the cell culture and viral multiplication could be carried out in situ in the same apparatus.