bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phosphorus uptake and growth of blue‐green alga, Microcystis aeruginosa
Authors: Okada Mitsumasa , Sudo Ryuichi , Aiba Shuichi 
Published: December 2004

AbstractThe specific uptake rate Qp of orthophosphate (expressed throughout as phosphorus) and the specific growth rate μ of Microcystis aeruginosa were measured using batch‐precultured cells, whose growth phase, and intracellular and extracellular phosphorus concentrations fp and P, respectively, had been changed. When the cells from phosphorus‐rich precultures were used, smaller values of Qp (0.1–0.3 μg P mg dry wt. −1 h −1) were observed. However, if phosphorusstarved cells were used, the initial value of Qp was enhanced to more than ten times those smaller values referred to above, but declined rapidly with time after the transfer. Qp leveled off at around t = 4 h, when fp approached the maximum value, even if phosphorus was still available in the medium. A new correlation was presented here with respect to Qp as a function of P and fp as follows:

Although numerical values of parameters involved in the equation depend on physiological state (or preculture history) of the cells, the above equation could account not only for phosphorus uptake, during which changes in phosphorus content in the cells were observed, but also for initial rates of uptake presented previously by other workers. μ Values were confirmed to be a hyperbolic function of fp as has been suggested by previous workers.
Photosynthetic regeneration of ATP using a strain of thermophilic blue–green algae
Authors: Sawa Yoshihiro , Kanayama Kazumi , Ochiai Hideo 
Published: December 2004

AbstractPhotosynthetic ATP accumulation was shown in the presence of exogenous ADP plus orthophosphate on illumination to the intact cells of a strain of thermophilic blue–green algae isolated from Matsue hot springs, Mastigocladus sp. Kinetic studies of various effectors on the ATP accumulation proved that the ATP synthesis depends mainly on the cyclic photophosphorylation system around photosystem I (PS‐I) in the algal cells. The temperature and pH optima for the accumulation were found at 45°C and pH 7.5. Maximum yield was obtained with light intensity higher than 15 mW/cm2. Borate ion exerted pronounced enhancement on the ATP synthesis. With a continuous reactor at a flow rate of 1 ml/hr at 45°C and pH 7.5, efficient photoconversion of ADP (2mM, at substrate reservoir) to ATP (1mM, at product outlet) has been maintained for a period of 2.5 days, though the efficiency has decreased in a further 2‐day period to the level of 0.5mM ATP/9.5 h of residence time.
Kinetics of biofilm nitrification
Authors: Tanaka H. , Dunn I. J. 
Published: December 2004

AbstractThe reaction rates (r and r) in the two‐step nitrification reaction were measured in a fluidized‐sand‐bed biofilm reactor under a range of steady‐state conditions with respect to bulk NH, NO, and O2 concentrations. It was shown from theory and experiment that under low NH concentration conditions, if the O2/NH concentration ratio in the bulk liquid is less than the stoichiometric coefficient (3.4 mg/mg), then oxygen will be rate limiting. In all experiments r decreased more than r under low oxygen conditions. This resulted in high NO effluent concentrations under low residence time conditions. The influence of the oxygen penetration effects on the relative values of r and r was experimentally shown to be caused either by the Nitrobacter location in the inner biofilm regions or by a Km effect for oxygen. Theoretical support of these findings was provided by a differential diffusion‐reaction model which was used to simulate the experimental results.
Studies on immobilized Saccharomyces cerevisiae. III. Physiology of growth and metabolism on various supports
Authors: Bandyopadhyay K. K. , Ghose T. K. 
Published: December 2004

AbstractIn earlier communications general analyses of rapid ethanol fermentation by Saccharomyces cerevisiae immobilized on inert supports were described. In this article physiology of growth and metabolism (parameters like rates of CO2 evolution and O2 uptake, respiratory quotient, and generation time) of Saccharomyces cerevisiae immobilized on different supports are reported. Values of the ratio of specific oxygen uptake rate for immobilized cells to free cells have been found to be 0.732, 0.781 and 0.785 for carrier A, carrier B, and covalently crosslinked controlled pore glass (CPG, specific surface area of 439 m2 g−1), respectively. Rates of specific CO2 evolution for immobilized cells to free cells for these supports are 0.784, 0.822, and 0.783, respectively. Marked reduction in generation time of Saccharomyces cerevisiae on all the supports has been observed. No change in size (4.8–5 μm) and specific growth rate (μm = 0.275 h−1) of cells leaving the reactor has been observed.
Identification of mass‐transfer parameters and process simulation of SCP production process in airlift tower reactors with an external loop
Authors: Luttmann R. , Buchholz H. , Zakrzewski W. , Schügerl K. 
Published: December 2004

AbstractA distributed parameter model for simulation of SCP‐production processes in tower reactors with an outer loop was developed by considering substrate, cell, and CO2 balances in the liquid phase, and O2 and CO3 balances in the ges phase and taking into account variations of dissolved oxygen concentration, pressure, and kLa along the column, as well as double substrate Monod kinetics. This model was used to describe the cultivation of Hansenula polymorpha in a tower‐loop reactor (height 275 cm, diameter 15 cm). Parameter identification and process simulation were carried out by a hybrid computer. The variation of identified mass transfer parameters with fermentation time and operation mode is considered employing ethanol and glucose substrate, respectively. Relationships among kLa, substrate concentration, and superficial gas velocity were developed to facilitate the layout and simulation of pilot‐plant reactors.
Immobilization of horse liver alcohol dehydrogenase on copolymers of glycidyl methacrylate and ethylene dimethacrylate
Authors: Kovář J. , Navrátilová M. , Skurský L. , Drobník J. , Švec F. 
Published: December 2004

AbstractAlcohol dehydrogenase has been immobilized to the basic copolymer and its several derivatives using various techniques. Enzyme coupling to the supports with amino groups by means of glutaraldehyde was found the most suitable. Activity of alcohol dehydrogenase coupled to these amino supports was comparable to that of the enzyme bound to Sepharose. Thermal and pH stability of alcohol dehydrogenase increased essentially upon immobilization. Kinetic properties of the immobilized enzyme differed from those of free alcohol dehydrogenase, pH optimum shifted to alkaline range, and apparent Michaelis constants for substrates and coenzymes increased. Curvatures observed in Lineweaver‐Burk plots for coenzymes suggest an involvement of diffusion effects in the reaction catalyzed by alcohol dehydrogenase linked to these polymers.
The influence of precipitation reactor configuration on the centrifugal recovery of isoelectric soya protein precipitate
Authors: Bell D. J. , Dunnill P. 
Published: December 2004

AbstractThe strength and rheological characteristics of isoelectric soya protein precipitate, prepared in continuous tubular and batch‐stirred tank reactors, were determined in relation to the separation efficiency and sludge discharge characteristics of intermittent disk and scroll discharge centrifuges. The batch tank precipitate showed greater resistance to aggregate shear breakup than the tubular reactor precipitate. This difference was of significance to the separation efficiency of the scroll centrifuge only. The tubular reactor precipitate sludge showed greater resistance to shear deformation and resulted in drier sludge for a given scroll differential speed. some compressive dewatering occurred for both types of precipitate sludge but shear‐induced dewatering is proposed as the major mechanism. This study illustrates the need to integrate the design of protein precipitate formation and centrifugal recovery operations.
Kinetic studies of enzymatic hydrolysis of insoluble cellulose: Analysis of the initial rates
Authors: Lee Yong‐Hyun , Fan L. T. 
Published: December 2004

AbstractA study was conducted on the kinetics of enzymatic hydrolysis of pure insoluble cellulose using unpurified culture filtrate Trichoderma reesei, with the emphasis on the initial reaction period. The initial hydrolysis rate and extent of enzyme (soluble protein)adsorption, either apparent or initial, were evaluated under various experimental conditions. It has been found that the various mass‐transfer steps do not control the overall hydrolysis rate and that the hydrolysis rate is mainly controlled by the surface reaction step promoted by the adsorbed enzyme. It has also been found that the initial hydrolysis rate strongly depends on the initial extent of soluble protein adsorption and the effectiveness of the adsorbed soluble protein to promote the hydrolysis. The initial extent of soluble protein adsorption, in turn, is related to the initial cellulose concentration, enzyme concentration, and specific surface area of cellulose, whereas the effectiveness of the initially adsorbed soluble protein to promote the derived to interrelate these parameters without resorting to the Michaelis–Menten kinetics. The present result appear to imply that the role of enzyme–substrate complex formation should not be ignored in deriving a mechanistic kinetic model for enzymatic hydrolysis of cellulose.
Continuous enzymatic liquefaction of starch for saccharification
Authors: Carr M. E. , Black L. T. , Bagby M. O. 
Published: December 2004

AbstractA process was explored for continuous enzymatic liquefaction of corn starch at high concentration and subsequently saccharification to glucose. The process appears to be quite efficient for conversion of starch to glucose and enzymatic liquefaction and should be readily adaptable to industrial fermentation processes. Preliminary work indicated that milled corn or other cereal grains also can be suitably converted by such a process. Essentially, the process involved incorporation of a thermostable, bacterial α‐amylase for liquefaction and, subsequently, of a glucoamylase into the continuous mixer under conditions conductive to rapid enzymatic hydrolyses. Also studied was the effect on substrate liquefaction of variable such as starch concentration (40–70° ), level of α‐amylase (0.14–0.4%, dry starch basis), temperature (70–100°C), pH (5.8–7.1), and residence time (6 and 12 min). The degree of liquefaction was assessed by determining (1) the Brookfield viscosity, (2) the amount of reducing groups, and (3) the rate and extent of glucose formed after glucoamylase treatment. Best liquefaction process conditions were achieved by using 50–60% starch concentration, at 95°C, with 0.4% α‐amylase, and a 6‐min residence period in the mixture. Under these conditions, rate and extents of glucose obtained after glucoamylase treatment approached those obtained in longer laboratory batch liquefactions. The amount of glucose formed in 24h with the use of 0.4% glucoamylase was 86% of theory after a 6‐min continuous liquefaction, compared to 90% for a 30‐min laboratory batch liquefaction (95°C, 0.4% α‐amylase).
Processes governing primary biofilm formation
Authors: Bryers James D. , Characklis William G. 
Published: December 2004

AbstractBiofilm accumulation under turbulent flow condition on the surface of a circular tube is the net result of several process including the following: (1) transport and firm adhesion of soluble components and microbial cell to the surface; (2) metabolic conversions within the biofilm in cluding growth and maintenance decay process; (3) detachment of portions of the biofilm and reentrainment in the bulk fluid. Experiments in tabular reactor were designed to measure the rates of these process during the early stages of biofilm accumulation as a function of the Reynolds number and suspended biomass concentration. Results indicate deposition (i.e., combined transport and adsorption) is only important in the very early stages of biofilm accumulation and is significantly influenced by negligible for the thin biofilms encountered in these experiments. Net biofilm production rates in all experiments decrease to same level and this level is not affected by changes in Reynolds number or suspended biomass concentration. Biofilm detachment rate increases continuously with biofilm accumulation and with increasing Reynolds number.
Effects of attachment of bacteria to chemostat walls in a microbial predator–prey relationship
Authors: Ratnam Diwakaran A. , Pavlou Stavros , Fredrickson A. G. 
Published: December 2004

AbstractMixed cultures of the protozoan Tetrahymena pyriformis and the bacterium Escherichia coli were propagated in chemostats fed with glucose and minimal mineral salts medium. The interior surfaces of some chemostats were treated with a silicone compound but those of other chemostats were not. Data obtained showed that bacteria but not protozoans were attached strongly to the walls of the chemostats, that silicone treatment reduced the density of the attached bacteria by two orders of magnitude or more, and that the presence of the attached bacteria had significant effects on the dynamics of the microbial predator–prey system. Attempts were made to simulate the data by various mathematical models. It was found that a model based on combination of the Topiwala–Hamer model for wall attachment and a multiple saturation model for growth of the protozoans on the bacteria gave a reasonable fit of all the data.
The effect of the oxygen transfer rate (OSR) on the formation of cellulases by Trichoderma viride in submersion culture
Authors: Škachová Helena , Gottvaldová Maria , Kučera Jiří , Podrazký Vladimíir 
Published: December 2004

AbstractThe formation of cellulases by Trichoderma viride in a medium containing cellulose as a sole source of carbon depends on the oxygen transfer rate (OSR); the OSR, on the other hand, depends on the concentration of cellulose in the medium because the concentration of cellulose strongly affects the viscosity of the medium. In the work presented here, the dependence has been determined for the oxygen transfer rate on geometric relations and viscosity in cellulose‐containing media during cultivation in shaken flasks, and the oxygen transfer rate on NRe' NG' and Na during cultivation in a laboratory fermentor of 3000‐mL volume. Two cellulosic materials have been compared with a different effect on viscosity: Microcrystalline beach cellulose and fibrous cellulose. It has been found that, in an applicable range of concentration, microcrystalline cellulose does not affect the oxygen transfer rate (at concentrations up to 3%). Fibrous cellulose increases the OSR during cultivation in shake flasks but decreases it during civilization in fermentors. On the basis of these results, the optimization has been carried out on the cultivation conditions in fermentors.
Enzyme immobilization by the coulomb force
Authors: Furusaki Shintaro , Asai Nobuhiro 
Published: December 2004

AbstractA new immobilization technique has been developed. It involves immobilizing enzymes on a porous polytetrafluoroethylene membrane with a nonporous polyurethane coat by the use of an electrostatic force, i.e. the Coulomb force. The immobilized enzyme can be recovered by supplying a reversed electrical potential. The reaction characteristics of the immobilized amyloglucosidase were studied using maltose as a substrate. The Michaelis constant becomes larger than that of the native enzyme, and depends on the electrical potential gradient in the solution.
Factors affecting the pretreatment of biomass with gaseous ozone
Authors: Neely W. C. 
Published: December 2004

AbstractTreatment of a wide variety of lignocellulosic biomass with gaseous ozone results in greatly enhanced susceptibility to cellulase enzyme hydrolysis and to digestion by rumen microorganisms so that it can be used as ruminant animal feed or for the production of glucose via enzymatic hydrolysis. By use of appropriate reaction conditions a useful degree of such pretreatment may be obtained in 1–2 h contact time with an ozone consumption of ca. 4–6% of the dry weight of the biomass.
Isolation of an inulinase derepressed mutant of Pichia polymorpha for the production of fructose
Authors: Bajon A. M. , Guiraud J. P. , Galzy P. 
Published: December 2004

AbstractPichia polymorpha has inulinase activity and could be used for the production of fructose syrup from inulin. The application of immobilized P. polymorpha whole cells for the continuous hydrolysis of inulin is, however, limited since the biosynthesis of this enzyme system is repressed by the reaction products, dextrose and fructose. A derepressed mutant hyperproducer of inulinase was isolated after treatment with EMS followed by a selection step with deoxyglucose.
Studies on nitrification of aniline with acclimated activated sludge
Authors: Kumar N. Jothi , Krishnamoorthi K. P. , Swaminathan T. 
Published: December 2004

AbstractAniline, a toxic, organic pollutant, occurs in a number of industrial effluents. Apart from carbonaceous oxygen demand, aniline imposes a nitrogenous oxygen demand, due to its nitrogen content, in excess of that required for cell growth. Incomplete biodegradation will result in ammonia production; this also exerts toxicity. Hence, nitrification of aniline should be ensured in the biological treatment before discharge into receiving streams. Aniline, however, is reported to inhibit the nitrification process. Aniline degradation was studied in laboratory continuous activated sludge with an acclimated culture developed in synthetic feed to determine the extent of complete biological degradation. Aniline–N (even at 400 mg/L aniline concentration)could be converted to nitrate–N with ammonium–N and nitrite–N formed as intermediates at a detention time of 24 h. The nitrification, however, was suppressed by aniline. The degradation of aniline to ammonia releases the suppression and the nitrification proceeds rapidly.
Accumulation of heavy‐metal ions by Zoogloea ramigera
Authors: Norberg Anders B. , Persson Hans 
Published: December 2004

AbstractBiomass has been produced from glucose using the organism Zoogloea ramigera 115. This biomass has been used to remove copper, cadmium, and uranyl ions from water solutions. The metal uptake was studied with two different methods: either by spectrophotometric measurements on the solutions after flocculation or by potentiometric measurements with amalgam electrodes in order to follow the entire complex formation. The metal–biopolymer interaction in 0.1M NaClO4 is practically the same as when no neutral salt is added. The metal uptake is dependent on pH and is selective. A reversible process suitable for metal complexation is described.
Continuous production of ethanol by yeast “immobilized” in a membrane‐contained fermentor
Authors: Kyung Kyu H. , Gerhardt Philipp 
Published: December 2004

AbstractA dialysate‐feed, immobilized‐cell dialysis continuous fermentation system was investigated as a method of relieving product inhibition in the conversion of glucose to ethanol by cells of Saccharomyces cerevisiae ATCC 4126. The substrate was fed into a continuous dialysate circuit and then into a batch fermentor circuit via diffusion through the microporous membranes of an intermediate dialyzer. Simultaneously, product was withdrawn from the fermentor circuit through the dialyzer membranes into the dialysate circuit and out in the effluent. Since the fermentor was operated without an effluent, the cells essentially were immobilized and converted substrate to product by maintenance metabolism. Contrary to prior results with this novel system for the continuous fermentation of lactose to lactate by lactobacillus cells, a steady state of yeast cells in the fermentor did not occur initially but was obtained by the depletion of medium nitrogen and the prevention of cell breakage, although the substrate and product concentrations then became unsteady. The inherent advantages of the system was offset in the ethanol fermentation by relatively low productivity, which appeared to be limited by membrane permeability.
Semicontinuous and continuous production of penicillin‐G by Penicillium chrysogenum cells immobilized in κ‐carrageenan beads
Authors: Deo Y. M. , Gaucher G. M. 
Published: December 2004

AbstractConidia of Penicillium chrysogenum were immobilized in K‐carrageenan beads and then incubated in a growth‐supporting medium to yield a penicillin producing immobilized cell mass. These in situ grown immobilized cells were used for the semicontinuous (replacement cultures)and continuous (fluidized bioreactor culture) production of penicillin‐G. When periodically replaced into a minimal production medium, immobilized cells exhibited a half‐life for penicillin production which was ninefold greater than that exhibited by free cells. The half‐life of penicillin production and the yield of penicillin from glucose in such a replacement culture were greatly affected by the frequency of replacement and by the production medium's pH and concentration of glucose, phosphate, and trace metal nutrients. A penicillin‐producing continuous flow bioreactor (150 mL), employing immobilized cells, was operated for up to 16 days. The best specific penicillin productivity (1.2 mg/g cells/h)yield from glucose (7.0 mg/g glucose) and half‐life of production (15 days) were obtained when the feed medium contained 10 g/L of glucose, the pH was maintained at 7.0, the relative dissolved oxygen concentration was ca. 40%; and the residence time was 20 h.
Preparation and characterization of a soluble dextran α1 proteinase inhibitor complex
Authors: Mitra G. , Coan M. H. 
Published: December 2004

AbstractPurified human α1 proteinase inhibitor, a plasma glycoprotein with a molecular weight of 5.3 × 104 daltons and a major serine protease inhibitor has been covalently coupled to dextrans with molecular weights of 1.77 × 104 and 1.03 × 104 daltons. The coupled conjugates were soluble in aqueous medium and stable up to 6 months at +5°C. Increased moles of dextran/mole protein ratio during coupling resulted in progressive decreases of inhibitory capacity, immunogenicity, and the association constant (kassoc) between the enzyme and the inhibitor. Compared to the native protein, the soluble conjugates showed improved stability at pH 3.0 and heat stability at 60°C. At 60°C, no loss of inhibitory capacity has been seen up to 60 min for the conjugates during which time the native protein lost greater than 90% of its inhibitory capacity. The presence of antioxidant catalase was needed to prevent oxidative degradation by hydrogen peroxide.