bluuebunny/crossref_metadata_2025_split huggingface dataset:
Saccharification of cellulose by the cellulolytic enzyme system of Thermomonospora sp. II. Hydrolysis of cellulosic substrates
Authors: Ferchak John D. , Hägerdal Bärbel , Pye E. Kendall 
Published: December 2004

AbstractA saccharification of cellulosic material using culture filtrate from the stationary phase of a culture of Thermomonospora sp. produced primarily cellobiose up to levels inhibitory to further saccharification, while the use of whole broth resulted in the production of glucose as well. Glucose production was enhanced and continued throughout the saccharification (24–36 hr) by several additions of cellobiase activity in the form of culture solids. Using Solka‐Floc as substrate, the “difference sugar” level (total soluble sugar minus glucose) rapidly rose to the same relatively stable concentration under various hydrolysis conditions, which was independent of the total sugar and glucose concentrations. A rapid hydrolusis rate was observed initially during saccharification, followed by a much slower rate of sugar production. Repeated centrifugation of the reaction mixture and replacement of the supernatant with fresh enzyme solution resulted each time in the reinitiation of a rapid hydrolysis rate. Saccharifications using A vicel microcrystalline cellulose, acid‐swollen cellulose, and cotton as substrates were also studied. A modified method of making phosphoric‐acid swollen cellulose is described. Saccharification of this substrate by culture filtrate and sequential additions of culture solids resulted in an inverse relationship between the attained glucose concentration and cellobiose‐cellotriose concentrations.
Enzymatic modification of vegetable protein: Mechanism, kinetics, and production of soluble and partially soluble protein in a batch reactor
Authors: Constantinides A. , Adu‐Amankwa B. 
Published: December 2004

AbstractEnzymatic hydrolysis of insoluble soybean protein by a protease enzyme produced by Penicillium duponti K 1104, was investigated in a batch reactor. The reaction conditions were 30–55°C and pH 3.4–3.7. The mechanism of solubilization of the insoluble protein by the Penicillium duponti enzyme was deduced from a series of experiments. Kinetic models were developed that involved adsorption followed by peptic digestion of protein, inhibition of low‐molecular‐weight peptides, and enzyme deactivation. The uncoupled kinetic parameters were estimated using the Marquardt nonlinear parameter estimation algorithm. A bang–bang production of soluble and partially soluble protein is suggested for higher productivity. The essential amino acids pattern of the enzyme‐Hydrolyzed soy protein was comparable with the unhydrolyzed protein isolate. Aggregation of the soluble protein for an extended time was observable. The low‐molecular‐weight soluble protein was incorporated into noncarbonated beverages. The amount of protein that could be incorporated into a can of 355 ml noncarbonated beverage, without observable changes in the optical density and also aggregation of the protein, was 2.5 g soluble protein. Beverages with caramel color showed excessive decrease in optical density and precipitation. The kinetics and diffusion in a multipore immobilized‐enzyme recycle reactor will be considered in part II of this series.
Continuous aerobic conversion of poultry waste into single‐cell protein using a single reactor: Kinetic analysis and determination of optimal conditions
Authors: Kargi F. , Shuler M. L. , Vashon R. , Seeley H. W. , Henry A. , Austic R. E. 
Published: December 2004

AbstractA single‐stage aerobic continuous process for the conversion of poultry waste into single‐cell protein is described. The slurried manure was supplemented by molasses. Kinetics and possible mechanisms for the suggested conversion‐scheme have been investigated. A Box–Wilson experimental design has been employed to elucidate the effect of environmental conditions on reactor performance. Temperature, pH, and percent solids concentration in the feed (media composition) were the independent process variables, while the minimum residence time for the nearly complete utilization of total uric acid and ammonia nitrogen, the amount of carbon required per gram of nitrogen consumed, and protein content of the product were considered as dependent variables. Optimal environmental conditions for the minimum raw material cost and for the maximum percent protein, lysine, and methionine content of the product were determined. The operating conditions of 25°C, pH 7.5, 1.5% solids in the feed, and a residence time of 8.1 hr were found to be the most appropriate conditions maximizing the “profit” function, which is defined as the difference between the product value and raw material cost.
Immobilized mitochondrial electron transport particle for NADH determination
Authors: Aizawa Masuo , Wada Mitsuo , Kato Seishi , Suzuki Shuichi 
Published: December 2004

AbstractNonphosphorylating electron transport particles (ETP) prepared from beef heart mitochondrion were immobilized in agar gel. The immobilized ETP showed an oxidase activity to both NADH and succinate. The immobilized ETP was reusable. An electrochemical device for the determination of either NADH or succinate was assembled consisting of the membrane‐bound ETP and an oxygen probe. The response to succinate was specifically inhibited by the addition of malonate.
Partition of hexadecane to the cell surface of Candida tropicalis: Mechanism for the transport of water‐insoluble substrates
Authors: Käppeli O. , Fiechter A. 
Published: December 2004

AbstractThe partition of hexadecane to the cell surface of Candida tropicalis was measured by incubating heat‐inactivated cells with hexadecane‐1‐14C on a gyratory shaker. The free hexadecane was separated by centrifuging the cells through a 15% sucrose solution, and the partitioned hexadecane was quantified by scintillation spectrometry of the samples from the resulting cell sediment. Heat‐inactivated cells did not take up hexadecane as determined by a membrane filtration technique involving organic solvent washing. The partitioning was a time‐dependent process. The velocity increased by increasing the shake rate of te shaker. At 360 rpm and with baffled flasks, saturation of the cell surface with hexadecane was obtained after a 20 min incubation period. The amount of hexadecane partitioned depended on the initial hexadecane‐to‐cell concentration ratio. At a ratio of 5 μmol/mg cell protein the highest amount of hexadecane partitioned was measured at 2100 μmol/mg cell protein. At ratios higher than 6 μmol/mg cell protein the cells were no longer sedimentable by centrifugation. The partition of hexadecane to the cell surface was affected by removing the surface layer of the cell wall by Pronase treatment and by using detergents in the partition assay. Pronase treatment lowered the amount of hexadecane partitioned as a consequence of the removal of the lipophilic layer of the cell surface. Detergents influence the partition coefficient and also lowered the amount of hexadecane partitioning to the cell surface. At a low shaking intensity (280 rpm, unbaffled flasks), after Pronase treatment, and in the presence of detergents he uptake of hexadecane by the cells was limited by the partitioning.
Analysis of microbial growth and product formation with Nitrate as Nitrogen source
Authors: Erickson L. E. 
Published: December 2004

AbstractMass balance regularities are used to develop equations for the estimation of maintenance coefficients, true growth yields, and true product yields when nitrate is the nitrogen source. An available electron balance is presented that includes the uptake of nitrate. The application of the theory is illustrated using continuous‐culture data of Stouthamer and Bettenhaussen in which Aerobacter aerogenes is grown aerobically with KNO3 as the nitrogen source.
Influence of very small bubbles on the dynamic kLA measurement in viscous gas–liquid systems
Authors: Heijnen J. J. , Riet K. Van't , Wolthuis A. J. 
Published: December 2004

AbstractExperiments reveal a fraction of tiny bubbles (≪1 mm) in viscous gas‐liquid systems. It is plausible that the oxygen tension is these bubbles will be in equilibrium with that in the liquid within seconds. This means that, as regards to such oxygen concentration changes as occur on kLA determination by the dynamic method, the “liquid‐small bubble dispersion” can be considered as a homogeneous phase. This leads to major corrections and, therefore, the application of the dynamic kLA method in viscous gas‐liquid systems will be problematic.
Modeling of rotating biological contactor systems
Authors: Wu Yeun C. , Smith Ed D. , Hung Yung T. 
Published: December 2004

AbstractAn investigation of the rotating biological contractor (RBC) process variables to determine the efficiency of biological oxygen demand (BOD) removal is presented. Operating parameters including influent BOD content (<355 mg/liter), flow rate, disk surface area, hydraulic loading, disk rotational speed, liquid retention time, stage number, and wastewater temperature were evaluated. The BOD predictive model was developed using literature data with multiple regression analysis. This study shows that influent BOD concentration, hydraulic loading, stage number, and wastewater temperature are the most significant variables in predicting the RBC system performance. The model presently developed was verified by field data concerned with the treatment of both domestic and low‐strength industrial wastewaters. Also, the results calculated by this model were compared to those obtained from Weng's model.
Human antibody immunosorption of hepatitis B surface antigen from blood and plasma
Authors: Areson Peter D. W. , Charm Stanley E. , Wong Bing L. 
Published: December 2004

AbstractRemoval of the Hepatitis B surface antigen (HBsAg) from whole blood and blood products, using human antibody (HBAb) immunosorbent, was studied and kinetics of complexing were monitored using radioimmunoassay (RIA). An intermittent complexing process was developed that minimizes damage to the cellular components of blood. HBsAg concentration in blood was reduced 1.5 to 2 logarithmic cycles in 3 hr with this system. Free HBsAg remaining in solution at equilibrium was further reduced by transferring the blood to a vessel containing unused immunosorbent. Through multiple stage treatment of a blood sample, it may be possible to reduce the probability of contamination with HBsAg to below the infectious level. This process may be applied to the selective removal of other proteins from blood and plasma.
Utilization of the white‐rot fungus Sporotrichum pulverulentum for water purification and protein production on mixed lignocellulosic wastewaters
Authors: Ek Mats , Eriksson Karl‐Erik 
Published: December 2004

AbstractA process has been developed that allows a direct conversion of lignocellulosic materials into fungal biomass. The thermotolerant white‐rot fungus Sporotichum pulverulentium has been used in continuous laboratory fermentations as well as in a 25 m3 batch fermentation. Fungal cell mass for feeding trials was produced and the economics of the process were estimated. The investigation shows that the process works satisfactorily on the small continuous scale as well as in the large batch culture. The process also seems easy to scale up. The economic evaluations show the conversion of solid lignocellulosic materials to protein feed is not feasible by our process unless the material to be fermented has a certain negative value. A mixed wastewater, such as the white water system in paper and fiber board mills, containing both water soluble mono‐ and oligosaccharides and solid lignocellulosic material, can, however, be fermented in an economically feasible way due to the combined effect of protein production and water purification. Data on the nutritional value of the product are presented in an accompanying paper.
Inhibition of alcoholic fermentation by substrate and ethanol
Authors: Moulin G. , Boze Hèlène , Galzy P. 
Published: December 2004

AbstractThe effect of ethanol and sugars on rates of fermentation was studied. We used a strain of Canadida pseudotropicalis. The specific rate of fermentation was determined by using the Warburg manometer. The effect of ethanol was formulated as an exponential function of ethanol concentration, but the empirical constant was different when glucose or lactose was used as a substrate. The effects of both ethanol and substrate were formulated. It was demonstrate that when lactose and glucose were present in the medium with a small amount of alcohol, a synergistic effect on the rate of fermentation appeard. This phenomenon considerably limits the rate of fermentation.
Oxidation of D‐glucose in the presence of glucose oxidase and catalase
Authors: Linek V. , Beneš P. , Sinkule J. , Holeček O. , Malý V. 
Published: December 2004

AbstractThe kinetics of oxidation of glucose solution by dissolved oxygen in the presence of glucose oxidase and excess catalase were studied both theoretically and experimentally. The kinetic model used was based on the detailed mechanism of the reaction. The description of the model is given by the Michaelis–Menten equation for the case of two substrates. The experiments were carried out in a closed reactor at a temperature of 25°C and pH 5.55. Commercial enzymes were used. Kinetic constants of the reaction were evaluated by fitting the oxygen concentration profiles calculated from the model to those found experimentally, by the method of nonlinear regression. The rate of D‐glucose mutarotation to α and β form, and distortion of data caused by the dynamics of the applied oxygen probe were taken into account. The determined kinetic constants of the reactions are in good agreement with those given in the literature for purified enzymes. Adoption of literature kinetic data of this reaction to the determination of aeration capacity of fermentors by means of glucose oxidase systems has proved possible.
Concentration of animal blood by ultrafiltration
Authors: Fernando T. 
Published: December 2004

AbstractPilot‐scale investigations into the application of ultrafiltration (UF) for concentrating bovine blood or a mixture of bovine and ovine blood are described. Tests were carried out in an Iopor 6CL UF system and a Romicon (hollow fiber) UF system. Optimal operating conditions for these two system were evaluated. Starting from a 18–20% TS lood concentration final concentrations of 28–30% TS were achieved. The lopor system was found to be more suited for processing blood and the average flux values obtained indicated UF to be a more economical process for concentrating blood than vacuum evaporation.
Production of yeast‐lytic enzymes by Cytophaga species in batch culture
Authors: Asenjo J. A. , Dunnill P. , Lilly M. D. 
Published: December 2004

AbstractThe conditions for culture storage, inoculum preparation, and growth of a Cytophaga species, constitutive with respect to yeast‐lytic enzymes, have been established in shake‐flask studies and in 5 liter fermentor experiments. A low cost medium was adopted for 900 liter‐scale fermentation and gave an enzyme activity in the fermentation broth somewhat greater than the comparable laboratory‐scale one.
Enzymatic hydrolysis of cellulose to glucose lung immobilized β‐glucosidase
Authors: Sundstrom D. W. , Klei H. E. , Coughlin R. W. , Biederman G. J. , Brouwer C. A. 
Published: December 2004

AbstractThe production of sugars by enzymatic hydrolysis of cellulose is a multistep process which includes conversion of the intermediate cellobiose to glucose by β‐glucosidase. Aside from its role as an intermediate, cellobiose inhibits the endoglucanase components of typical cellulase enzyme systems. Because these enzyme systems often contain insufficient concentrations of β‐glucosidase to prevent accumulation of inhibitory cellobiose, this research investigated the use of supplemental immobilized β‐glucosidase to increase yield of glucose. Immobilized β‐glucosidase from Aspergillus phoenicis was produced by sorption at controlled‐pore alumina with about 90% activity retention. The product lost only about 10% of the original activity during an on‐stream reaction period of 500 hr with cellobiose as substrate; maximum activity occurred near pH 3.5 and the apparent activation energy was about 11 kcal/mol. The immobilized β‐glucosidase was used together with Trichoderma reesei cellulase to hydrolyze cellulosic materials, such as Solka Floc, corn stove and exploded wood. Increased yields of glucose and greater conversions of cellobiose of glucose were observed when the reaction systems contained supplemental immobilized β‐glucosidase.
Biosorption of uranium and thorium
Authors: Tsezos Marios , Volesky Bohumil 
Published: December 2004

AbstractSelected samples of waste microbial biomass originating from various industrial fermentation processes and biological treatment plants have been screened for biosorbent properties in conjunction with uranium and thorium in aqueous solutions. Biosorption isotherms have been used for the evaluation of biosorptive uptake capacity of the biomass which was also compared to an activated carbon and the ion exchange resin currently used in uranium production processes. Determined uranium and thorium biosorption isotherms were independent of the initial U or Th solution concentration. Solution pH affected the exhibited uptake. In general, lower biosorptive uptake was exhibited at pH 2 than at pH 4. No discernible difference in uptake was observed between pH 4 and pH 5 where the optimum pH for biosorption lies. The biomass of Rhizopus arrhizus at pH 4 exhibited the highest uranium and thorium biosorptive uptake capacity (g) in excess of 180 mg/g. At an equilibrium uranium concentration of 30 mg/liter, R. arrhizus removed approximately 2.5 and 3.3 times more uranium than the ion exchange resin and activated carbon, respectively. Under the same conditions, R. arrhizus removed 20 times more thorium than the ion exchange resin and 2.3 times more than the activated carbon. R. arrhizus also exhibited higher uptake and a generally more favorable isotherm for both uranium and thorium than all other biomass types examined.
Preliminary studies on the use of internal carbon sources in the removal of nitrogen from sewage with a model treatment system using alternating aerobic and anaerobic conditions
Authors: Battley E. H. 
Published: December 2004

AbstractA description is presented of the design and performance of a model sewage treatment system consisting of one aerobic reactor and clarifier plus one anaerobic reactor, with an aerobic‐mixed‐liquor‐volume/anaerobic‐mixed‐liquor‐volume ratio of 1:4. Effluent values of ammonia, nitrite, and nitrate nitrogen were found to be 0, 0, and about 5 ppm, respectively. Effluent organic nitrogen was not determined, having been assumed to be negligible. Approximately 90% of the total influent nitrogen was removed by nitrification plus denitrification. Sludge production was found to be minimal, and it was never necessary to waste sludge from the system.
Casein hydrolysis in stirred tank reactors using chymotrypsin immobilized on magnetic supports
Authors: Munro P. A. , Dunnil P. , Lilly M. D. 
Published: December 2004

AbstractNickel‐NiO‐BSA‐chymotrypsin has been used to hydrolyze casein in both batch and continuous stirred tank reactors. The kinetics of hydrolysis in both types of reactor were considered. Some operational problems encountered using fine powder catalysts in batch stirred tank reactors are discussed. High gradient magnetic separation was found to be a powerful catalysts retention method for magnetic support particles, particularly when using a ferromagnetic collection matrix. Nickel particles of diameter 3–7 μm were easily separated from water at a processing velocity of 39 mm/sec. Nickel powder and precipitated Fe3O4 were also separated satisfactorily using a rotating drum magnetic separator.
The use of calcium alginate gels for “solids separation” and “diffusional chromatography” of biological materials
Authors: Kierstan M. 
Published: December 2004

AbstractThe use of calcium alginate gels for the “Solids Separation” techniques was demonstrated by entrapment of a yeast extract in calcium alginate pellets and the study of the release of alcohol dehydrogenase and NADH into a dilute calcium chloride solution. The use of calcium alginate gels for a “Diffusional Chromatography” technique was demonstrated in a model system by a fractionation of NAD and hemoglobin release following their entrapment in calcium alginate pellets. The advantages of these techniques and their potentials are discussed.
Evaluation of feeding strategies in carbon‐regulated secondary metabolite production through mathematical modeling
Authors: Bajpai R. K. , Reuß M. 
Published: December 2004

AbstractThere is now growing evidence that the production of many secondary metabolic by microorganisms is subjected to carbon‐catabolite regulation. Even though the exact mode of this regulation is not yet clear, an engineering analysis of the production process is still possible based upon a suitable hypothesis. By way of simulation of penicillin fermentation data obtained from the literature, a mechanistic model involving a substrate inhibition kinetics of product formation has been verified in this paper. Such a model has been found successful not only in predicting simple sugar‐feeding strategy, but also a complicated computer guided strategy based upon controlling biomass growth rates in the tropo and idiophases. Using this model, for strategies for sugar feeding into penicillin fermentation have been investigated. These results show that similar penicillin productivities can be obtained using any of these strategies provided fermentations are carried out under optimal conditions corresponding to the strategy chosen. Effect of maximum oxygen transfer capacity of the fermentor under the conditions of fungal growth has been incorporated using an upper limit of biomass concentration on achievement of which the fermentations must be stopped due to serious oxygen limitations. Results of model simulations with such limits throw light upon the way in which different fermentors may behave with respect to product formation.
Microelectrode studies of oxygen transfer in trickling filter slimes*
Authors: Chen Y. S. , Bungay H. R. 
Published: December 2004

AbstractSlime‐covered rocks and samples of process waters from two trickling filters for treatment of municipal wastes were brought to the laboratory for probing with microelectrodes to determine dissolved oxygen (DO). Slime thickness was 0.4–1.5 mm. Flow rate of medium over the slime had a minor effect on slime respiration, but pH 5 or below was strongly inhibitory. Increasing temperature showed lower oxygen concentration throughout a slime, although 27°C had results little different from those at 22°C. Medium concentration had a profound effect on oxygen concentration profiles, and either oxygen‐limited or substrate limited respiration could be demonstrated. Illumination of slimes from the top of the trickling filter developed oxygen supersaturation because oxygen from photosynthesis could not diffuse away rapidly.