bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enzymatic properties and application of L‐asparaginase–collagen membrane
Authors: Morikawa Yasushi , Karube Isao , Suzuki Shuichi , Nakano Yosuke , Taguchi Tetsuo 
Published: December 2004

AbstractThe activity of the L‐asparaginase–collagen membrane was 3.4 U/mg membrane (5.8 U/cm2 membrane) and the activity yield was 29%. The apparent Michaelis constant of the asparaginase–collagen membrane was 5.9 × 10−3M. The operational half‐life of the immobilized asparaginase column was 35–40 days. The L‐asparaginase–collagen membrane retained 90% of its original activity after ethylene oxide gas sterilization. The dried membrane stored at room temperature retained its original activity for five months, and the membrane stored in 0.05M phosphate buffer (pH 8.0) retained its original activity for one week at 37°C. The L‐asparaginase–collagen membrane tanned with 1% glutaraldehyde was stable against proteolytic enzymes. Complete degradation of L‐asparagine by the L‐asparaginase–collagen membrane occurred at a low concentration. The L‐asparagine in dog blood plasma was completely degraded within 20 min by the extracorporal shunt using the L‐asparaginase–collagen membrane.
Biomethanation: Anaerobic fermentation of CO2, H2 and CO to methane
Authors: Wise D. L. , Cooney C. L. , Augenstein D. C. 
Published: December 2004

AbstractStudies to examine the microbial fermentation of coal gasification products (CO2, H2 and CO) to methane have been done with a mixed culture of anaerobic bacteria selected from an anaerobic sewage digestor. The specific rate of methane production at 37°C reached 25 mmol/g cell hr. The stoichiometry for methane production was 4 mmol H2/mol CO2. Cell recycle was used to increase the cell concentration from 2.5 to 8.3 g/liter; the volumetric rate of methane production ran from 1.3 to 4 liter/liter hr. The biogasification was also examined at elevated pressure (450 psi) and temperature to facilitate interfacing with a coal gasifier. At 60°C, the specific rate of methane production reached 50 mmol/g cell hr. Carbon monoxide utilization by the mixed culture of anaerobes and by a Rhodopseudomonas species was examined. Both cultures are able to carry out the shift conversion of CO and water to CO2 and hydrogen.
Preparation of succinylated yeast protein: Composition and solubility
Authors: Vananuvat P. , Kinsella John E. 
Published: December 2004

AbstractA method for the succinylation of yeast Proteins during their isolation is described. Some factor affecting the extent of succinylation are described, e.g., heating of protein (80°C for 5 min) prior to dervatization reduced maximum succinylation of available ε‐amino groups from 88 to 54%. Succinylation of amino groups progressively increased as the concentration of succinic anhydride was increased and there was a concomitant decrease in nucleic acid content of the precipitated protein concentrate from 12.5 to 5.3 for 0 and 88% succinylation, respectively, succinylation enhanced the solubility of the protein concentrates particularly below pH 7 and it decreased the isoelectric point pH. 4.5 to 4.0.
Process design and economic studies of alternative fermentation methods for the production of ethanol
Authors: Cysewski Gerald R. , Wilke Charles R. 
Published: December 2004

AbstractCell recycle and vacuum fermentation processes are described for the continuous production of ethanol. Preliminary process design studies are employed to make an economic comparison of these alternative fermentation schemes with continuous and batch fermentation technologies. Designs are based on a production capacity of 78,000 gal 95% ethanol (EtOH)/day employing molasses as the fermentation substrate. The studies indicate that a 57% reduction in fixed capital investment is realized by continuous rather than batch operation. Further decreases in required capital investment of 68 and 71% over batch fermentation were obtained for cell recycle and vacuum operation, respectively. However, ethanol production costs were dominated by the cost of molasses, representing over 75% of the total manufacturing cost. But, when a reasonable yeast by‐product credit was assumed, the net production cost for 95% ethanol was estimated at 82.3 and 80.6 cent/gal, for the cell recycle and vacuum processes, respectively.
Practical design equations for trickling‐filter process
Authors: Kong M. F. , Yang P. Y. 
Published: December 2004

AbstractThe concept of solid retention time (SRT) was applied in the trickling‐filter process. A rational model of the trickling‐filter process employing activated‐sludge‐process operational parameters was presented. The design equation was developed as follows; 1/SRT = [(S0 − Sn)/X]·(F/V)·Y − kd, where SRT is the sludge retention time, S0 is the influent substrate concentration; Sn is the effluent substrate concentration; X is the total cell mass retained per unit filter volume; V is the total volume of the filter; F is the influent flow rate; Y is the cell yield, and kd is the cell decay rate. A laboratory‐scale trickling‐filter pilot plant treating synthetic sucrose waste‐water was studied to verify the present design equation. The solid retention time was evaluated from the total slime mass (active and inactive) retained and the sludge wasted daily. It was found that the present design equation could be applied for designing the trickling‐filter process by the application of SRT employed in the activated sludge process. Also, the SRT could be related to the hydraulic loading and influent substrate concentration for a given filter medium. The variation of SRT by the hydraulic loading at constant organic loading was observed and could be expressed by the mechanistic model. When SRT was maintained more than 12 days, it provided the highest five‐day biological oxygen demand (BOD5) removal, minimum sludge production, and lowest sludge volume index (SVI) value. The present model does include both microbial growth kinetic concepts, which can be more practical and meaningful for the design of a trickling filter.
Immobilization of aminoacylase by adsorption to tannin immobilized on aminohexyl cellulose
Authors: Watanabe Taizo , Mori Takao , Tosa Tetsuya , Chibata Ichiro 
Published: December 2004

AbstractThe immobilization of aminoacylase (N‐acylamino acid amidohydrolase, EC 3.5.1.14) was investigated by using tannin immobilized on aminohexyl cellulose. The most active immobilized aminoacylase was obtained when aminoacylase was adsorbed to the immobilized tannin in a weak alkaline medium containing sodium chloride and n‐butanol at 37°C. The activity of the immobilized tannin–aminoacylase complex per unit volume was five times higher than that of the DEAE‐Sephadex–aminoacylase complex used for industrial production of L‐amino acids in our plants. The half‐life of the immobilized tannin–aminoacylase complex was 20 days under continuous operation at a high concentration of substrate; on the contrary, that of the DEAE‐Sephadex‐aminoacylase complex was 0.5 days.
Biomass recycling and species competition in continuous cultures
Authors: Weissman Joseph C. , Benemann John R. 
Published: December 2004

AbstractA chemostat with cell feedback is analyzed for three kinds of limiting nutrient: a substrate dissolved in the inflow, a gas bubbled directly into the reactor, and light. The effects of recycle are distinct in each case, because the relationships between hydraulic detention time and nutrient inflow are different for each type of nutrient, Effluent recycle, in which the recycle stream is more dilute than the reactor, is discussed in terms of cell detention time and nutrient limitation. Results from chemostat cultures of the blue‐green alga, Spirulina geitleri, demonsrtat cell feedback under light limitation. Maximum Productivity is fixed by the incident light intensity. At a particular dilution rate recycling increases or decreases productivity by taking cell density closer or further from the optimum density. Cell recycle with heterogeneous populations can change the outcome of species competition. Selective recycling of one species can reverse this outcome or stabilize coexistence by its selective effect on cell detention time. Experimental results from light‐limited mixed cultures of S. geitleri and a Chlorella sp. verify this.
Immobilization and characterization of D–amino acid oxidase
Authors: Parkin Kirk , Hultin Herbert O. 
Published: December 2004

AbstractOptimal conditions with respect to pH, concentration of glutaraldehyde and enzyme, and order of addition of enzyme and crosslinking reagent were established for the immobilization of hog kidney D‐amino acid oxidase to an attapulgite support. Yields of 40 to 70% were generally attained although when low concentrations of enzyme were used yields were consistently greater than 100%. It is suggested that this is due to a dimer → monomer shift at low protein concentrations. The stability of soluble D‐amino acid oxidase was dependent on the buffer in which it was stored (pyrophosphate‐phosphate >borate > Tris). Stability of immobilized enzyme was less than soluble in pyrophosphate‐phosphate buffer, but storage in the presence of FAD improved stability. In addition, treatment of stored, immobilized enzyme with FAD before assay restored some of its activity. The immobilized D‐amino acid oxidase was less stable to heat (50°C) than the soluble enzyme from pH 6 to 8 but was more stable above and below these values. Apparent km values for D‐alanine, D‐valine, and D‐tryptophan decreased for the immobilized enzyme compared to the soluble.
Identification of metabolic model: Citrate production from glucose by Candida lipolytica
Authors: Aiba Shuichi , Matsuoka Masayoshi 
Published: December 2004

AbstractThe concept of mass balance was used to analyze the metabolic pathways of citrate production by Candida lipolytica from glucose. Specific rates of glucose consumption, citrate and isocitrate productions, carbon dioxide evolution, and cellular syntheses of protein and carbohydrate were observed in an NH4+‐limited chemostat culture. These data permitted one to assess the carbon flux in vivo by solving simultaneous carbon balance equations with respect to intermediary metabolite pools in the steady State. Among the three models considered here, model I (which coordinates the pyruvate carboxylation with the tricarboxylic acid cycle, but disregards the glyoxylate cycle) was considered plausible because the carbon flux calculated so far was acceptable. On the other hand, models II and III (which overlook the pyruvate carboxylation and the 2‐oxoglutarate dehydrogenation, respectively) were found to be most unlikely because of the unusual flux assessed from these models.
Rapid ethanol fermentation of cellulose hydrolysate. I. Batch versus continuous systems
Authors: Ghose T. K. , Tyagi R. D. 
Published: December 2004

AbstractRapid fermentation of bagasse hydrolysate to ethanol under anaerobic conditions by a strain of Saccharomyces cerevisiae has been studied in batch and continuous cultures at pH 4.0 and 30°C temperature with cell recycle. By using a 23.6 g/liter cell concentration, a concentation of 9.7% (w/v)ethanol was developed in a period of 6 hr. The rate of fermentation was found to increase with supplementation of yeast vitamins in the hydrolysate. In continuous culture employing cell recycle and a 0.127 v/v/m air flow rate, a cell mass concentration of 48.5 g/liter has been achieved. The maximum fermentor productivity of ethanol obtained under these conditions was 32.0 g/liter/hr, which is nearly 7.5 times higher than the normal continuous process without cell recycle and air sparging. The ethanol productivity was found to decrease linearly with ethanol concentration. Conversion of glucose in the hydrolysate to ethanol was achieved with a yield of 95 to 97% of theoretical.
New nonsynthetic medium for Rhizobium culture production from wastes
Authors: Gulati S. L. 
Published: December 2004

AbstractA nonsynthetic medium was formulated for placement of mannitol fully by saccharified pea husk (Pisum sativum L.) and water hyacinth (Eichhoornia crassipes) with Trichoderma viride QM 9414 and molasses. Yeast extract was Partially replaced by proteolysed pea husk, water hyacinth, and mycelium of T. viride QM 9414 by boiling 4 hr with 5% (v/v) HCl. The rhizobial growth was equal in both standard yeast extract mannitol (YEM) and formulated nonsynthetic media. However, barring Rhizobium phaseoli (urid) E‐6, the rhizobial counts in thenon‐synthetic medium were higher then the counts in YEM medium. In the fermentor, rhizobial growth was also almost equal to YEM medium. These results indicated that costly ingredients like mannitol and yeast extract can be replaced by hydrolysates of pea husk, water hyacinth, mycelium of T. viride, and molasses.
Use of an enzyme thermistor in continuous measurements and enzyme reactor control
Authors: Danielsson Bengt , Mattiasson Bo , Karlsson Roland , Winqvist Fredrik 
Published: December 2004

AbstractThe enzyme thermistor measures the heat produced by the action of an immobilized enzyme on a substrate present in the sample. Its application in analysis of discrete samples, e.g., in clinical chemistry, is well documented, but it has not been used so far for continuous measurements. We describe here the application of the enzyme thermistor for continuous monitoring and control of enzyme reactors. An enzyme thermistor filled with coimmobilized glucose oxidase and catalase was used to measure the amount of glucose in the outflow from a column reactor containging immobilized lactase acting on a lactose solution pumped through the reactor. The lactose conversion was kept on a constant level, irrespective of the actual enzymatic activity in the reactor, by regulating the flow through the reactor. The experiments were carried out with aqueous solutions of lactose as well as with whey from cow's milk.
Action of shear on enzymes: Studies with catalase and urease
Authors: Thomas C. R. , Dunnill P. 
Published: December 2004

AbstractIntermittent shear was applied to approximately 1 mg/ml solutions of bovine liver catalase in a coaxial cylindrical viscometer at temperatures from 20 to 60°C and shear rates up to 683 sec−1. The viscometer was sealed to prevent evaporation. Up to 40°C there were no activity losses during 3 hr total shearing. Above 40°C shearing reduced losses due to thermal inactivation, possibly by interfering with precipitation. At 3440 sec−1 and 40°C fine precipitates formed but little activity was lost. No activity losses were found with experimental conditions under which Taylor vortexing occurred, nor when shear stresses were increased up 57 times by adding glycerol to raise the, viscosity. There were no significant losses in a capillary rheometer at shear rates up to 106 sec−1. When low concentration (6 μg/ml) catalase solutions were sheared there was little loss in sealed systems, but there were losses in “open” systems even in low‐temperature nonshear experiments. Although there were no losses with 1 mg/ml solutions, 6 μg/ml catalase solutions from an alternative source did lose activity in sealed systems but much less than expected from previously published work. Approximately 1 mg/ml jack bean urease solutions were sheared in the sealed system at 23°C and 683 sec−1 for 3 hr. No losses were found. No evidence of temporary or permanent inactivation was found with 28°g/ml solutions sheared in the presence of urea. Shear forces alone were not found to be as effective in causing enzyme inactivation as is generally believed and alternative mechanisms for damage are discussed.
Effect of pore diffusion limitation on dextrin hydrolysis by immobilized glucoamylase
Authors: Lee Douglas D. , Lee Gene K. , Reilly Peter J. , Lee Yoon Y. 
Published: December 2004

AbstractData reported here and previously indicate that when dextrin is hydrolyzed in the presence of immobilized glucoamylase, use of a larger average molecular weight substrate leads to lower overall rates of hydrolysis, while the maltose concentration during the bulk of the reaction and the maximum glucose concentration are lower than when the soluble form of the enzyme is employed under the same conditions. Computer simulation of the system demonstrated that all three observations were caused by pore diffusion limitation: the first by slow diffusion of substrate, the second by slow diffusion of intermediates, and the third by slow diffusion of glucose. Follow‐up experiments with glucoamylase immobilized to particles of different sizes confirmed this finding, as results with the smallest beads were identical to those with soluble glucoamylase.
Simple model for the energetics of growth on substrates with different degrees of reduction
Authors: Roels J. A. 
Published: December 2004

AbstractA simple model is developed for the energy transformation in growing microbial systems. The model is based on a linear equation for ATP consumption in the processes of growth and maintenance. A combination of this equation with macroscopic balances for the various components, the systems exchanges with the environment, and application of the concepts of the elementary balance allow the derivation of linear equations for the exchange of substrate, oxygen, and carbon dioxide with the environment. For growth on one sole carbon and energy source the model allows the definition of a critical substrate yield are expected and below which is decreasing substrate yield and energy supply growth limitation are expected. This restriction can be interpreted in a variety of other ways. It supplies a rationale for non‐energy‐production‐coupled transfer of hydrogen to oxygen or wasteful expenditure of ATP in growth on highly reduced substrates. It also allows the formulation of a limit to the maximum yield on oxygen that can never be exceeded in growth on highly reduced substrates.
Immobilization of β‐galactosidase and other enzymes onto p‐amino‐carbanilated cellulose derivatives
Authors: Beddows C. G. , Mirauer R. A. , Guthrie J. T. 
Published: December 2004

Abstractβ‐Galactosidase and other enzymes were immobilized on p‐amino‐carbanilated derivatives of cellulose and methylol cellulose using the diazo method and through glutaraldehyde. The optimum conditions for coupling cellulose tri‐(p‐amino‐carbanilate) (CTAC) to β‐galactosidase were established. The diazo coupling method with CTAC gave greater activity than with glutaraldehyde when coupled to β‐galactosidase (Escherichia coli). The stability of the CTAC–β‐galactosidase system was examined. The disubstituted p‐amino‐carbanilate derivative (CDAC) gave a lower activity, whereas the methylol analog (MCTAC) gave slightly greater activity. The CTAC was also used to immobilize glucose oxidase, trypsin, pepsin, and papain.
Characteristics of hexadecane partition by the growth medium of Acinetobacter sp.
Authors: Käppeli O. , Finnerty W. R. 
Published: December 2004

AbstractThe partition of n‐hexadecane in the spent growth medium of Acinetobacter sp. HOI‐N was determined by measuring the increase in the relative aqueous solubility of 3H‐hexadecane as compared to controls. The amount of hexadecane partitioned was proportional to the protein concentration. The specific solubility of hexadecane (nmol/mg protein) was analyzed by least‐squares fitting yielding an average slope of 0.6 with a standard deviation of 0.3, indicating either nonequilibrium of hexadecane or physical aggregation of protein. The amount of hexadecane partitioned was concentration dependent yielding optically clear microemulsions at hexadecane concentrations of less than 1.4mM and macroemulsions at hexadecane concentrations of 1.4mM or greater. Preliminary results indicated that hexadecane and partitioned by a lipoprotein complex.
Immobilization and properties of Leuconostoc mesenteroids dextransucrase
Authors: Kaboli Hossein , Reilly Peter J. 
Published: December 2004

AbstractDextransucrase from Leuconostoc mesenteroides (NRRL B‐512F) was purified by ultrafiltration and gel filtration chromatography in 54% yield. The specific activity of a heart cut was 58.6 U/mg; cumulative purification of that preparation was 247−fold. Of 13 carriers surveyed, only alkylamine porous silica gave immobilization efficiencies consistently above 15 %. Immobilization to silica changed the properties of dextransucrase relatively little, the optimum pH for activity remaining at 5.2, while that for stability decreased from pH 5.5−6 to pH 5.2. In short assays, highest activities of both soluble and immobilized dextransucrase occurred at 30°C. Activation energies below that temperature were 8.6 kcal/mol for the former form and 1.7 kcal/mol for the latter. Maximum stabilization of soluble dextransucrase was attained by 5mM Ca2+.
Amperometric determination of choline with use of immobilized choline oxidase
Authors: Matsumoto Kunio , Seijo Hideji , Karube Isao , Suzuki Shuichi 
Published: December 2004

AbstractCholine oxidase (choline: oxygen oxidoreductaserpar; was immobilized on a partially aminated polyacrylonitrile membrane. The enzyme electrode, consisting of an immobilized‐enzyme membrane and an oxygen probe, was employed for the determination choline. Dissolved oxygen consumption by the enzymatic reaction was measured amperometrically. The rate assay method was used for the choline determination. The response time of the sensor was 7 sec for choline. The choline assay was done within 1 min. The choline calibration curve was linear from 0 to 0.1mM. The response was reproducible within an average relative error of 2.3% when 0.2mM choline was employed for experiments. The choline in the fermentation media was determined by the sensor. Furthermore, phospholipids in the serum were also determined with native phospholiphase D and the enzyme electrode.
Ethanol production in an immobilized‐cell reactor
Authors: Sitton O. C. , Gaddy J. L. 
Published: December 2004

AbstractBiomass can be converted to sugars by hydrolysis with enzymes or mineral acids. These sugars can be converted into a number of chemical intermediates in biological reactors. Biological reactions are generally slow and selection of the most efficient reactor is important in these applications. Immobilized‐cell reactors allow high cell densities and high throughput by attaching the microorganisms to a fixed support. This paper examines the rate of production of ethanol from glucose by Saccharomyces cerevisia in a packed column. These rates are compared with those for the same reaction in a stirred reactor.