bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biological kinetic behaviors and operational performances in aerated and oxygenated systems
Authors: Yang P. Y. 
Published: December 2004

AbstractBiological kinetic behaviors of the oxygenated and aerated activated sludge process were studied and compared in both once‐through and constant sludge recycle systems. The models derived by Herbert, Elsworth, and Telling [J. Gen. Microbiol., 14, 601 (1956)] and Ramanathan and Gaudy [Biotechnol. Bioeng., 11, 207 (1969)] were used for the studies of once‐through and constant sludge recycle systems, respectively. Soft drink waste water was used for the growth limiting substrate. Temperature was controlled within 30 ± 2°C. The influent substrate concentration was maintained at 1,000 mg/liter. The experiments were conducted at various dilution rates (from \documentclass{article}\pagestyle{empty}\begin{document}$ \frac{1}{9} $\end{document}
to 1/1.0 hr−1), and recycle solids concentration values (from 5,000 to 10,000 mg/liter), with hydraulic recycle ratio, α, at 0.3.Biological kinetic constants were evaluated and compared. It was found that these constants were different for the aerated and oxygenated systems within a certain range of dilution rates studied. The critical dilution rates for diluting out effluent chemical oxygen demand (COD) occurred at 0.1 and 0.2 hr−1in the once‐through operation, and 0.2 and 0.4 hr−1in the sludge recycle operation for aerated and oxygenated systems, respectively. Observed sludge yield values and specific growth rate were varied with the type of aeration and with and without constant sludge recycle concentration applied. Sludge carbohydrates and proteins content in the oxygenation system (cell recycle) were 10.1–21.6% and 35.6–52.2%. Sludge volume index in the air and oxygenation systems varied from 41.4 to 354 and 31.9 to 58.5, respectively.
1,4‐α‐Glucan phosphorylase from Klebsiella pneumoniae covalently coupled on porous glass
Authors: Wengenmayer Friedrich , Linder Dietmar , Wallenfels Kurt 
Published: December 2004

AbstractA simplified procedure for the preparation of 1,4‐α‐glucan phosphorylase from Klebsiella pneumoniae is described. An 80‐fold purification is achieved in two steps with an overall yield of about 50%. The specific activity of the homogeneous enzyme protein is 17.7 units/mg. Compared with glycogen phosphorylase from rabbit muscle the enzyme from K. pneumoniae shows a markedly higher stability against deforming and chaotropic agents. The 1,4‐α‐glucan phosphorylase was covalently bound to porous glass particles by three different methods. Coupling with glutaraldehyde gave the highest specific activity, i.e., 5.6 units/mg of bound protein or 133 units/g of glass with maltodextrin as substrate. This corresponds to about 30% of the specific activity of the soluble enzyme. With substrates of higher molecular weight, such as glycogen or amylopectin, lower relative activity was observed. The immobilized enzyme preparations showed pH activity profiles which were slightly displaced to higher values and exhibited an increased temperature stability.
Electric field control of lipase membrane activity
Authors: Karube Isao , Yugeta Yoichi , Suzuki Shuichi 
Published: December 2004

AbstractLipase (EC 3.1.1.3., from Pseudomonas sp.) was entrapped in collagen membrane containing liquid crystal (4‐methoxybenzilidene‐4′‐n‐butylaniline). The activity of the lipase–liquid crystal membrane at an applied voltage of 4 V was 3.4 compared to a membrane tested without imposition of an external electric field. A linear relationship was observed between the activity of the lipase–liquid crystal membrane and the current. The apparent Michaelis constant (K′m) of the lipase–liquid crystal membrane under electric field was identical to that of the membrane under ordinary condition. Activation of the lipase–liquid crystal membrane was observed repeatedly, i.e., activation in the presence of an electric field and reversion to a basal level upon removal of the field occurred cyclically. Activity control of immobilized enzymes is desirable for switching devices of a bioreactor. Possible mechanisms of the lipase activation by electric field are discussed.
Electrochemical evaluation of lactate dehydrogenase immobilized in polyacrylamide gels
Authors: Chen A. K. , Liu C. C. 
Published: December 2004

AbstractLactate dehydrogenase (EC 1.1.1.27) has been immobilized in polyacrylamide gels over a platinum grid matrix. The immobilized enzyme is used to oxidize L‐lactate in the presence of nicotinamide adenine dinucleotide (NAD+) and femcyanide. The NADH produced is then chemically oxidized back to NAD+by ferricyanide. The coupled reduction of ferricyanide ions to ferrocyanide ions results in a measurable electrochemical potential. This measurable zero‐current potential is found to be Nernstian in nature and directly proportional to the logarithm values of L‐Iactate concentration over the range of 2 × 10−5to 5 × 10−2M. The results indicate that immobilized lactate dehydrogenase can be incorporated into a system to detect L‐Lactate acid in aqueous solutions.
Mechanistic model for microbial growth on hydrocarbons
Authors: Mallee F. M. , Blanch H. W. 
Published: December 2004

AbstractBased on available information describing the transport and consumption of insoluble alkanes, a mechanistic model is proposed for microbial growth on hydrocarbons. The model describes the atypical growth kinetics observed, and has implications in the design of large scale equipment for single cell protein (SCP) manufacture from hydrocarbons. The model presents a framework for comparison of the previously published experimental kinetic data.
Preliminary cost estimates for commercial fermentation of straw as animal feed
Authors: Grant G. A. , Anderson A. W. , Han Y. W. 
Published: December 2004

AbstractA preliminary cost estimate was made for two fermentation processes that increase the feed value of grass straw. In one method, straw hydrolyzed with dilute sulfuric acid is fermented by yeast. In the second method, the straw is treated with alkali, then inoculated with cellulolytic bacteria. Both processes increase the digestibility, protein content, and fat content of straw. Production costs estimated for plants processing 100 tons of straw/day by the two methods, were 80 to 88 dollars/ton. Capital costs were estimated at 5.2 million dollars for the acidhydrolysis yeast‐fermentation process and at 3.1 million dollars for the alkalicellulolytic bacteria process. Labor, capital, and energy were significant cost factors for both processes. Caustic costs were important in the alkaline‐treatment cellulolytic bacteria process.
Rapid biodegradation of calcium lignosulfonate by means of a mixed culture of microorganisms
Authors: Ban S. , Glanser‐Šoljan Margareta , Smailagić M. 
Published: December 2004

AbstractIn this paper we discuss the aerobic biodegradation of calcium libnosulfonate (CLS) in a beechwood sulfite waste liquor by means of a mixed culture of microorganisms consisting of two Trichosporn Years and bacteria in the Arthrobacter (two species), Psedomonas, and Chromobacterium genera. Under the established parameters 50% CLS was biodegraded in 24 hr accompanied by the demethylation of methoxyl groups, the splitting of sulpher–carbon bonds, and the appearance of carbonyl and carboxyl groups. The achieved results by determination of phenolic OH groups, as well as established changes of the absorption bands of IR spectra of the CLS molecule and the results of the shortening of the analyses of the C, H, O, and S, show that the degradation of the aromatic nuclei‐culture biodegradation, which confirms the increase in the concentration of conjugated carbonyl groups and carboxyl groups.
Enzymatic lysis of yeast cell walls
Authors: Knorr D. , Shetty K. J. , Kinsella J. E. 
Published: December 2004

AbstractLysis of yeast cell walls using zymolase and lysozyme was studied. During coupled zymolase–lysozyme treatment, nearly three times more reducing sugars were released from the yeast cells compared to controls. Enzyme treatment followed by extraction at pH 9 resulted in a yield of more than 80% of the total nitrogen of the yeast cell. Protein degradation occurred during enzyme treatment. The precipitation of proteins was significantly increased by succinylation after enzyme treatment. This also reduced the nucleic acid content of the yeast proteins to less than 2% and enhanced the extractability of nitrogenous material.
Comparison of dynamic oxygen electrode methods for the measurement of KLa
Authors: Ruchti G. , Dunn I. J. , Bourne J. R. 
Published: December 2004

AbstractThe dynamic oxygen electrode method for measuring KLa requires the use of a dynamic process model. Six models from the literature are described and compared with respect to their accuracy and ease of use. It is shown theoretically that for sufficient accuracy KLa should be less than the inverse electrode response time. Experimental measurements demonstrate their application to viscous and nonviscous systems. The liquid diffusion film is shown to cause an important measurement lag that can be accounted for by a first‐order time delay. Investigation on the influence of the experimental starting conditions show the importance of the gas and hold‐up dynamics. A new method is proposed to simplify the KLa calculation and to eliminate errors caused by starting conditions. This method, which accounts for gas, film, and electrode dynamical effects, requires only a simple semilog plot of the response data.
Determination of the specific growth of molds on semi‐solid cultures
Authors: Carrizalez V. , Rodríguez H. , Sardiña I. 
Published: December 2004

AbstractThe determination of growth constant of Aspergillus niger were obtained for semisolid cultures on cassava flour, Manihot esculenta, as a sole carbon source. As a consequence, a technique was developed that consisted of the use of a packed‐bed microfermentor with a working volume of 16 cm3. The bed consisted of gelatinized and granulated cassava flour containing mineral nutrients and mold spores. The carbon dioxide produced during the respiration was drawn off with a current of air and then absorbed in a solution of sodium hydroxide. The absorption of CO2, P, was correlated with the specific growth rate μ, by means of the equation P=Keμt, where t is time and K is a constant. Ammonium nitrogen was used as a limiting substrate and its concentration was varied from 0.039 to 2.5% in dry base. The maximum growth rate, μmax, and the saturation constant, Ks, were 0.31 hr−1 and 0.065 mmol (NH4)2SO4/g total dry solids. Substrate inhibition was presented and the constant ki gave a value of 1.5 mmol (NH4)2SO4/g total dry solids. The proposed method is highly recommended for the evaluation of the semisolid fermentation of molds and for strictly aerobic bacteria and yeasts. It can be used especially in the evaluation of the growth of microorganisms on peanut shells, coffee residues, sugar cane bagasse, and other agricultural wastes.
Utilization of partially N‐succinylated derivatives of chitosan and glycolchitosan as supports for the immobilization of enzymes
Authors: Yamaguchi Ryuji , Arai Yuji , Kaneko Takeshi , Itoh Tatsuro 
Published: December 2004

AbstractPolymer ampholites, partially N‐succinylated chitosans (PSC), and partially N‐succinylated glycolchitosans (PSGC) were prepared from chitosan (an N‐deacetylated chitin) and glycolchitosan (a partially O‐2‐hydroxyethylated chitosan), and they were utilized as novel supports for the immobilization of enzymes. The immobilization was conducted simultaneously with gelation of PSC and PSGC by reaction with water‐soluble carbodiimide in the presence of enzymes. Enzymes were covalently bonded on PSC and PSGC chains. Maximum activity yields of glucoamylase, β‐fructosidase, and D‐glucose isomerase were 58.8, 64.3, and 65.2%, respectively. Favorable activity yields of glucoamylase and β‐fructosidase were attained with PSC and PSGC having high degree of N‐succinylation, but those of D‐glucose isomerase were not affected by the degree of N‐succinylation (DS). The activity of immobilized glucoamylase was retained up to 85.5% over 30 batch reactions.
Continuous‐culture studies on the regulation of tylosin biosynthesis
Authors: Vu‐Trong K. , Gray P. P. 
Published: December 2004

AbstractThe metabolic regulation of tylosin synthesis by Streptomyces fradiae NRRL 2702 was studied in batch and chemostat cultures using a soluble synthetic medium. In batch culture a medium which diminished the trophophase‐idiophase kinetic pattern was used to assess the activities of the enzymes involved in tylosin synthesis. The enzymes methylmalonyl‐coenzyme A carboxyltransferase (EC 2.1.3.1) and propionyl‐coenzyme A carboxylase (EC 6.4.1.3) showed early enzymatic derepression, both enzymes reaching their highest specific activities after 72–96 fermentation. The activity of macrocin 3′ ‐O‐methyltransferase, the enzyme catalyzing the conversion of macrocin (tylosin C) to tylosin (tylosin A). also peaked at 72 h. The specific activities of the three enzymes showed close correlation with the qtylosin value. In chemostat cultures the activities of the enzymes and the intracellular level of the adenylate pool and energy charge were studied as a function of dilution rate. Under steady‐state conditions, increases in the specific growth rate repressed the enzymes activities with a concomitant increase in the intracellular level of the adenylate pool, while the adenylate energy charge remained almost constant and in the range 0.5–0.52. The highest specific activities of the enzymes were observed when D = 0.008 h −1. The specific rate of tylosin synthesis was inversely proportional to the specific growth rate and the intracellular level of adenylate pool. The pool of adenylate could be a nutritional parameter which had a considerable influence on the biosynthesis of tylosin.
Immobilized microbes and a high‐rate, continuous waste processor for the production of high Btu gas and the reduction of pollutants
Authors: Messing R. A. 
Published: December 2004

AbstractMicrobes capable of degrading organic wastes (sewage) are densely packed (immobilized) within the pores of controlled‐pore ceramics. When the ceramic displays the optimum pore range for the reproduction of these microbes, the minimum volume for a very efficient reactor is required. A two‐stage, anaerobic, immobilized microbe reactor has been designed, and laboratoryscale units have been constructed. A few of these units have been operated continuously for two years. These reactors were designed for the efficent conversion of carbon to methane in biodegradable molecules and for the effective transfer of that gas. The reactors were operated at 20, 30, and 40°C at residence times of 2–5.5 h. The total chemical oxygen demand (COD) of the sewage varied from 800–2600 mg/L. The resulting gas contained greater than 90% methane and less than 5% CO2. Approximately 32–54% of the influent total carbon was recovered as methane. The reduction in COD varied from 63 to 89%.
Growth characteristics of bakers' yeast in ethanol
Authors: Wasungu Kowda M. , Simard Ronald E. 
Published: December 2004

AbstractThe influence of temperature (15° −40°C) and pH (2.5–6.0) on the continuous growth of bakers' yeast (Saccharomyces cerevisiae) at steady state in 1% ethanol was investigated. Optimal temperature and pH were 30°C and 4.5, respectively. The short‐term effect of ethanol concentration (0.1–10.0%) on the yeast growth was assessed in batch culture. Up to 1% of ethanol, the yeast growth increased in function of the ethanol concentration in the medium. The biomass reached a maximum within the interval of 1–4% of ethanol (7.9 and 31.6 g/L, respectively) and decreased at higher concentrations. The residual ethanol concentration in the medium increased rapidly when the initial ethanol concentration exceeded 4%. The best‐fit model obtained for growth inhibition as a function of ethanol concentrations was that of Tseng and Wayman: μmS/)K + S( − i (S − Sθ). With this model, the specific growth rate (μ) decreased linearly as the ethanol concentration increased between the threshold value (Sθ) of 11.26 g/L to be fully inhibited at 70.00 g/L (S;) an inhibition constant (i) of 0.0048 g L−1 h−1, a maximum specific growth rate (μm) of 0.284 h−1, and a saturation constant (K) of 0.611 g/L were obtained.
Diffusive and hydraulic transfer of solutes through homogeneous membranes
Authors: Sada Eizo , Katoh Shigeo , Miyai Kiyosato , Terashima Masaaki , Yoshida Shuichi 
Published: December 2004

AbstractRates of hydraulic transport of water, solute permeabilities, and sieving coefficients of homogeneous κ‐carrageenan and bovine serum albumin membranes were measured. These values increased with the water content of membranes. The data show good agreement with the predictions based on the pore model.
Studies on Scenedesmus acutus growth II. Effect of autotrophic and mixotrophic growth on the amino acid and the carbohydrate composition of Scenedesmus acutus
Authors: Shamala T. R. , Drawert F. , Leupold G. 
Published: December 2004

AbstractAs a general rule an increase in carbohydrates occurs during the light phase of the cell cycle and that of protein during phase, although variations were found in these components under autotrophic and mixotrophic growth conditions. The results are based on the quantitative determination of carvohydrates as trimethylsilyl (TMS) derivatives and amino acids as N‐trifluoroacetyl‐n‐butyl (TAB) esters in algal cells cultured in light and dark periods by gas‐liquid chromatography (LC). Cells harvested during the dark period contained more amino acids as compared to similar cultures harvested during the light phase. In light, the production of amino acids of the aspartate family increased in cells cultivated with glucose and carbon dioxide. With glucose as sole carbon source, the carbohydrate content was higher in the dark than in the light period. Under continuous light conditions, in the presence of carbon dioxide, there was a decrease in the carbohydrate content also. Gas–liquid chromatography analysis of the extract of the purified cell walls showed that they are made up of 0.076% carbohydrates and 0.28% amino acids on the dry weight (DW) basis of whole cells. The results on the metabolism of cells, under autotrophic and mixotrophic conditions, are discussed in this article.
The kinetics of yeast growth and nicotinic acid production
Authors: Tseng Murray M‐C. , Phillips Colin R. 
Published: December 2004

AbstractProduction of nicotinic acid from Saccharomyces cerevisiae in exponential growth on glucose was found to be growth associated, and in the stationary and decline phase was found to be death associated. A kinetic model was developed to describe the kinetics of growth of S. cerevisiae and the production of nicotinic acid.
A collagen–alkaline phosphatase conjugate membrane: Enzymatic kinetics in‐vitro stability
Authors: Jefferies Steven R. , Gutmann James L. 
Published: December 2004

AbstractCollagen‐alkaline phosphatase membranes have been prepared, and their enzymatic kinetics and in‐vitro stability analyzed. Collagen–alkaline phosphatase dispersions were prepared by complexation in aqueous alkaline solution and cast into membranes by controlled dehydration. These membranes were then crosslinked in glutaraldehyde solution, washed thoroughly, and dried. Crosslinking in glutaraldehyde confers increased stability of catalytic activity to these collagen–enzyme membranes, especially when compared to uncrosslinked collagen–alkaline phosphatase membranes assayed in a similar fashion. Crosslinking in glutaraldehyde also appears to inhibit gross leaching of the soluble enzyme from the carrier matrix. Apparent intrinsic kinetic properties of the collagen–alkaline phosphatase conjugate were analyzed in membranes of various thickness in order to determine the effect of internal diffusion resistances on the kinetics of the immobilized enzyme. The apparent Michaelis constant of the immobilized enzyme decreased as a function of decreasing membrane thickness, reaching an observed apparent Michaelis constant of 1.6mM at a membrane thickness of 0.2 mm. Extrapolation of the apparent Michaelis constant to zero membrane thickness, using a linear plot of the natural logarithm of the apparent Michaelis constant versus membrane thickness, allowed estimation of the true Michaelis constant of the immobilized enzyme. The estimated value for the true Michaelis constant of the collagen–alkaline phosphatase complex was 0.7mM. This value agrees closely with reported values for several purified mammalian alkaline phosphatase. The apparent Michaelis constant for the 0.2mm collagen‐enzyme membrane agrees closely with the Michaelis constant reported for an alkaline phosphate purified from chondrocyte matrix vesicles. The intrinsic maximum reaction velocity (Vm) of the collagen–enzyme complex was estimated b plotting the observed reaction rate as a function of decreasing membrane thickness and extrapolating such plots, at various substrate concentrations, to the limiting case of zero membrane thickness. The maximum reaction velocity was obtained by the common intercept of these plots as they approached zero membrane thickness.
Mathematical description of competition between two and three bacterial species under dual substrate limitation in the chemostat: A comparison with experimental data
Authors: Gottschal Jan C. , Thingstad T. Frede 
Published: December 2004

AbstractA mathematical model is presented which describes the growth of two bacterial species in mixed chemostat cultures under dual substrate limitation. Competition experiments between a facultatively chemolithotrophic Thiobacillus and either a heterotroph or an obligately chemolithotrophic Thiobacillus served as an experimental model system [Gottschal, de Vries, and Kuenen, Archives of Microbiology, 121, 241–249 (1979)]. Furthermore, the introduction of Monod‐type growth kinetics in the model allowed an assessment of the relative importance of the growth parameters for the outcome of the competition. In addition, it is shown how the results of the mathematical description of the two‐membered mixed cultures can be used to predict the outcome of the competition between the three species competing for the two growth‐limiting substrates acetate and thiosulfate in a three‐membered mixed culture. In contrast to the experimental data of Gottschal, de Vries, and Kuenen it is predicted that two of the three species or only one of them (the “mixotroph”) will survive in the culture. Within the framework of the proposed mathematical model, two possible explanations for the experimentally observed coexistence of three species are suggested: either the very slow dynamics of the system did not allow the attainment of a true steady state within the time scale of the present experiments or some parameters describing the mixed culture were extremely sensitive towards minor fluctuations in dilution rate. The results of the present mathematical model support the view that facultatively chemolithotrophic bacteria are able to survive under appropriate limiting mixed substrate conditions in the presence of more “specialized” heterotrophs and obligately chemolitotrophs, in spite of their relatively low specific growth rate.