bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhancement factor for oxygen absorption into fermentation broth
Authors: Yagi Hideharu , Yoshida Fumitake 
Published: December 2004

AbstractValues of the enhancement factor for oxygen absorption into fermentation broth, i.e., the ratio of the liquid phase mass transfer coefficients for oxygen absorption for both cases with and without respiration of microorganisms were predicted theoretically on the assumption of various cell concentration distributions. Calculations indicate that in the usual case the enhancement factor is only slightly or negligibly larger than unity, even when accumulation of microorganisms at or near the gas‐liquid interface is assumed. Results of experiments with sparged‐stirred fermentors on oxygen absorption into fermentation broths containing resting and growing cells of Candida tropicalis confirmed the theoretical prediction. Except for extreme cases, the effect of respiration of microorganisms on kLa, values can practically be ignored.
The effect of acid pH on the growth kinetics of Trichoderma viride
Authors: Brown D. E. , Halsted D. J. 
Published: December 2004

AbstractBatch cultures of Trichoderma viride have been carried out in a 10 liter stirred fermenter at controlled pH values of 2.5, 2.7, 3.0, and 4.0, and without pH control at a temperature of 28°C. Cell and glucose concentrations and dissolved oxygen values are reported. The yield coefficient was found to be constant at 0.40 kg cells/kg glucose and the maximum specific growth rate was linearly correlated with the hydrogen ion concentration.
Dynamic and steady state studies of phenol biodegradation in pure and mixed cultures
Authors: Der Yang Ren , Humphrey Arthur E. 
Published: December 2004

AbstractThe microbial degradation of phenol by pure and mixed cultures of Pseudomonas putida was studied in batch, phenol‐stat, and continuous culture systems. In the continuous culture runs, both steady state and transient experiments were performed. From these experiments, a model for the kinetic behavior of the organisms was evolved and an analysis performed on the stability and dynamic behavior of pure and mixed cultures. The results indicate that it should be possible to achieve phenol removal from wastewaters down to levels of 1‐2 ppm in a single stage system. However, because of the effects of substrate inhibition on kinetic behavior of the microorganisms, long lasting transients can occur. The transient behavior of such systems cannot be solely determined from μmax or Ks, parameters, but must include a consideration of the transient size and response characteristic of the organism.
Production of plant virus inhibitor by Phytolacca americana suspension culture
Authors: Misawa Masanaru , Hayashi Mineyuki , Tanaka Hozumi , Ko Keido , Misato Tomomasa 
Published: December 2004

AbstractThe inhibitory activity of tobacco mosaic virus (TMV) infection was assayed with the extracts of various callus tissues derived from the intact plants. Phytolacca americana callus was selected as a producer of the virus inhibitor and its cultural conditions in suspension were examined for cell growth and the inhibitor production. A modified liquid medium containing twofold concentrations of all components in that of Murashige and Skoog plus 2,4‐D (1.0 mg/liter) and sucrose (6%), but without any vitamins and glycine was chosen for production of higher levels of the inhibitor. TMV infections in tobacco, bean, and tomato plants were markedly inhibited by the introduction of the disrupted whole broth of suspension cultured P. americana.
An evaluation of a ceramic monolith as an enzyme support material
Authors: Benoit Michel R. , Kohler Joseph T. 
Published: December 2004

AbstractCatalase was immobilized on commercially available monolithic catalyst supports and also on participate support obtained by crushing the monolith. The kinetics of the monolith‐ and particulate‐supported enzymes were analyzed in a continuous tubular reactor system and pressure drop was also monitored. Analysis of the results indicates that the monolith‐supported system presents very little resistance to flow which results in a considerably smaller pressure drop than is obtained in flow through particulate‐supported systems under comparable conversion conditions. Ceramic monoliths thus appear to be very suitable for use as enzyme supports in continuous tubular reactor applications, particularly where high pressure drops might be expected.
Kinetics for activated sludge process design: Experiment application to straw paper wastewater treatment
Authors: Del Borghi Marco , Migliorini Giorgio , Isola Giacomo , Ferraiolo Giuseppe 
Published: December 2004

AbstractDegradation kinetics for the treatment of straw paper wastewater in an activated sludge process have been studied and a kinetic model has been derived for both batch and continuous experiments. These two methods are reasonably equivalent only when rather low concentrations of substrate are involved. In other cases batch and continuous results are quite different. Both models, however, show a dependence upon concentration corresponding to that which is typical of multicomponent substrate degradation. The kinetic model derived from continuous tests appears to be more suitable for designing industrial processes in that it avoids oversizing of the aeration unit.
Pectinolytic activity of Saccharomyces fragilis cultured in controlled environments
Authors: Wimborne Margaret P. , Rickard Pamila A. D. 
Published: December 2004

AbstractSeven of 30 yeast stock cultures, covering nine genera, and 13 of 39 yeasts isolated from grapes gave positive reactions when screened for pectinolytic activity on pectin gel plates. The seven stock cultures covered six species and four genera. Only one of the yeasts, Saccharomyces fragilis Y49, excreted discernible pectinolytic activity into the fluid of shake flask cultures; the activity was partially constitutive and was repressed by high oxygen tensions.
Experimental operation of immobilized multienzyme systems in optimal and suboptimal configurations
Authors: Chang Ho Nam , Reilly Peter J. 
Published: December 2004

AbstractTwo mixed immobilized enzyme systems, glucoamylase–glucose isomerase and glucose isomerase–glucose oxidase–catalase, were operated to verify theoretical predictions that optimal bifunctional catalyst configutations could exist superior to those where the catalysts were mixed uniformly or arranged sequentially in a tubular reactor. The experimental results for all three configurations conformed to the theoretical values sufficiently closely to support of optimal catalyst profiles.
Mathematical modeling of lag phases in microbial growth
Authors: Pamment N. B. , Hall R. J. , Barford J. P. 
Published: December 2004

AbstractThis paper describes a mathematical model of the lag phases of Saccharomyces cerevisiae that incorporates the basic concepts previously presented in a two‐stage deterministic model for the growth of this organism under conditions of oxygen excess with a sugar as the growth‐limiting substrate. The model structure was suggested by an extensive investigation of the causes of the lag phases of S. cerevisiae which found that, in contrast to the traditionally accepted trends, the length of the lag phase was not inoculum‐size dependent. This was consistent with other previously published work which suggested that a major factor in the length of the lag phases in S. cerevisiae was the need to synthesize adequate levels of glycolytic and respiratory enzymes. These suggestions were confirmed experimentally with lag‐age data. Based on this conclusion a mathematical model was developed incorporating a description of the levels of glycolytic and respiratory enzymes and their effect on the growth rate and metabolism. This model was tested experimentally and the initial results indicate indicate that many aspects of the lag phase of this organism may be described mathematically. The experimental findings further support the concept of primary regulatory control proposed by Bijkerk and Hall.
Role of formaldehyde in the utilization of C1 compounds via the ribulose monophosphate cycle
Authors: Papoutsakis Eleftherios , Lim Henry C. , Tsao George T. 
Published: December 2004

AbstractFormaldehyde, an intermediate in methanol oxidation, plays an important role in controlling methanol utilization by microorganisms which fix carbon via the ribulose monophosphate (RMP) cycle. The extracellular formaldehyde concentration profiles in batch cultures at low and high starting methanol concentrations with and without the presence of semicarbazide in the media, suggest the role played by formaldehyde. The impact of formaldehyde on growth is demonstrated by the time dependent and the initial methanol concentration‐dependent cell‐mass‐yield coefficient. Kinetic studies of the enzymes involved in the oxidation and incorporation of C1 units suggest that enzyme inhibition cannot account for the observed growth inhibition. A mechanism is proposed to explain methanol and formaldehyde utilization that stresses the transcriptional regulation of mass flow around formaldehyde in assimilation and oxidation pathways through repression and induction.
Immobilized α‐chymotrypsin: Pore diffusion control owing to pH gradients in the catalyst particles
Authors: Halwachs W. , Wandrey C. , Schügerl K. 
Published: December 2004

AbstractThe fast enzymatic hydrolysis of D,L‐phenylalanine methylester (DLE) to L‐phenylalanine (LA) and D‐phenylalanine methylester (DE) with immobilized α‐chymotrypsin was chosen as a model reaction. Under the experimental conditions applied in the present investigations the pore diffusion is the rate‐limiting step of this reaction owing to the pH gradient in the particles. The effectiveness of the catalyst is experimentally determined as a function of the substrate concentration based on measurements of the enzyme protein content of native and immobilized enzyme. The proteolytic reaction is theoretically treated by also using a pore diffusion model which takes into account the concentration gradients of substrate and product, pH‐ and enzyme activity profiles, as well as the change of buffer capacity of the solute in the catalyst particles. The model parameters were experimentally determined for the investigated system. It can be shown that conditions are possible for which the effectiveness of the catalyst exceeds unity.
Kinetics of enzymatic hydrolysis of cellulose: Analytical description of a mechanistic model
Authors: Okazaki M. , Moo‐Young M. 
Published: December 2004

AbstractA generalized mechanistic model for the enzymatic hydrolysis of cellulose is developed and expressed mathematically. The model is based on Michaelis–Menten‐type kinetics for concurrent random and endwise attack of the substrate involving end‐product inhibitions and three types of enzymes: an endo‐β;‐1,4‐glucanase, an exo‐β‐1,4‐glucanase, and β‐glucosidase. Basic parameters of the model which can explain synergistic and other effects observed experimentally are quantified and discussed. It is shown that cellulose degradation kinetics are expected to be strongly affected by the ratio of endo‐ to exocellulases in the reaction mixture as indicated by previous experimental data, and the substrate degree of polymerization, a factor not fully appreciated in previous studies, which appear to be overridingly important in many practical cases.
Continuous determination of ethanol during aerobic cultivation of yeasts
Authors: Bach H. P. , Woehrer W. , Roehr M. 
Published: December 2004

AbstractA new sensor for the continuous determination of ethanol during the production of yeasts, growing aerobically on fermentable sugars, is described. The operating principle is based on the detection of ethanol vapor in the exit air. A description of the sensor with a diagram of the measuring electronics is supplied. It was designed for the determination of ethanol contents up to 3 g/liter in aqueous solutions at 30°C. The sensitivity is very high — 1 ppm ethanol being detectable under these conditions. The aeration rate dose not affect the output signal in a wide range (0.5–2 v/v/m). Besides the unspecific sensitivity of the sensor to other easily oxidizable substances, the influence of the pO2 in the exit air, however, must be taken into account. The application of the sensor is shown in a fed‐batch culture of bakers' yeast where aerobic fermentation is caused by increasing the glucose feed rate.
Deactivation studies of immobilized glucose oxidase
Authors: Krishnaswamy S. , Kittrell J. R. 
Published: December 2004

AbstractStudies have been performed in a tubular flow reactor to characterize the deactivation of immobilized glucose oxidase. The effects of oxygen concentration in the range of 0.09 to 0.467mM and hydrogen peroxide concentrations in the range of 0.1 to 10mM were studied. A simple mathematical model assuming first‐order reaction and deactivation was found to describe the deactivation behavior adequately. The deactivation rate constant was found to increase with increasing levels of feed oxygen. Hydrogen peroxide was found to deactivate the enzyme severely and the deactivation rate constants were higher than those for oxygen deactivation. The influence of external and internal diffusion effects on the deactivation rate constant were examined. Although diffusional restrictions were negligible for oxygen transfer to the pellet, they were significant for transfer of hydrogen peroxide to the bulk stream. Increasing deactivation rates. Severe internal diffusion limitations were observed for the glucose oxidase system. However, for particle sizes in the range of 500 to 2000 μm, no effect on the rate of deactivation of the enzyme was observed.
Automatic assay of cellulase activity during fermentation
Authors: Leisola Matti , Kauppinen Veli 
Published: December 2004

AbstractAn automatic method using dyed cellulose as a substrate was developed to determine the solubilizing activity of a cellulase complex. The automatic analyzer was connected to a fermentor and enzyme activity was successfully assayed during fermentation. A useful sampling arrangement was developed and the analysis was sensitive enough to make a short reaction time possible. Cellulase production with Trichoderma viride was used as a model process.
Synthetic media for production of quality xanthan gum in 20 liter fermentors
Authors: Cadmus M. C. , Knutson C. A. , Lagoda A. A. , Pittsley J. E. , Burton K. A. 
Published: December 2004

AbstractXanthan gum is a heteropolysaccharide synthesized by Xanthomonas campestris NRRL B‐1459 and is composed of D‐glucose, D‐mannose, and D‐glucuronic acid, in addition to acetic and pyruvic acids. Different amounts of pyruvic acid ketal are found in various preparations which can influence the viscosities of dilute xanthan solutions. Polysaccharide production on synthetic media was studied in small‐scale fermentors. Fermentation conditions were established for production of both high and low pyruvic acid gums (about 4 and 2% pyruvic acid, respectively). Low nitrogen [0.1% (NH4)2HPO4] and air (0.25 vol/liter/min) levels favor production of low pyruvate gum; increasing (NH4)2HPO4 to 0.15%, adding K2HPO4, and increasing the air flow to 1.5 vol/liter/min favored production of normal gum. Both processes gave xanthan yields of 50 to 60%, based on 2.5% initial D‐glucose substrate, in two to three days. Differences in pyruvic acid content and in the quantity of gum produced under a given set of conditions were attributed to strain variability. Substrains were isolated that have desirable characteristics for production of xanthan gum; i.e., the ability to give good yields of high‐pyruvate gum when grown on both complex and synthetic media.
Studies on the stability of immobilized xanthine oxidase and urate oxidase
Authors: Johnson D. B. , Coughlan M. P. 
Published: December 2004

AbstractThe stability of immobilized preparations of xanthine oxidase and urate oxidase was studied, and optimized, because of the potential joint use of both enzymes in clinical analysis. Xanthine oxidase was immobilized on cellulose, Sepharose, hornblende, Enzacryl‐TIO, and Porous glass. The half‐lives of these preparations at 30°C ranged from 40 min to 5.0 hr. In this respect immobilized enzyme resembled soluble enzyme in dilute solution (0.11 mg/ml), when the half‐live was about 3.5 hr. More concentrated enzyme solution (1 mg/ml), had a half‐life of 64 hr, and was, therefore, considerably more stable than the untreated immobilized xanthine oxidase preparations. Inclusion of albumen in storage and assay buffer increased the half‐life of bound xanthine oxidase. So also did treatment with glutaraldehyde: in the case of xanthine oxidase bound to Enzacryl‐TIO such treatment increased the half‐life at 30°C from 3 hr to about 100 hr. Immobilized xanthine dehydrogenase was more stable than immobilized xanthine oxidase: the dehydrogenase lost no activity during continuous assay for 5 hr at 30°C. The stability of immobilized urate oxidase depended on the quantity of enzyme used and on the time of stirring during immobilization: thus a preparation was made (by stirring urate oxidase (48 mg/g support) with Enzacryl‐TIO for 24 hr) which lost no activity during 350 hr at 30°C.
Immobilization of immunoglobulins on polystyrene latex beads: Characterization by density gradient centrifugation
Authors: Genung Richard K. , Hsu Hsien‐Wen 
Published: December 2004

AbstractIsopycnic banding by density gradient centrifugation was used to measure density changes in complexes formed by the immobilization of each of four different immunoglobulins (IgG) (bovine, dog, rabbit, and sheep) on polystyrene latex beads (0.109 ± 0.0025 μm diam). Subtractive measurements of density changes allowed calculation of the mass of immobilized lgG under varying experimental conditions. The immobilization data were correlated with adsorption isotherms which incorporated charge repulsion forces. The effects of pH and NaCl concentration on the immobilization were studied for the latex–bovine lgG system. It was found that the mass of immobilized immunoglobulins was increased from 10 to 20% by removing the lgG from its isoelectric range.
Design, construction, and operation of some all‐glass pilot‐plant fermetors
Authors: Baker K. 
Published: December 2004

AbstractThe design, Construction, and operation of a 400 liter all‐glass fermentor, made from industrial glass Components, is described in detail. Outline details are also given for 100 and liter vessels of similar construction. The performance of the 400 liter fermentor with a variety of organisms is discussed. Harvesting performance. Using a disk‐stak centrifuge, is also described.
Response to various shock loadings of the constant recycle‐sludge‐concentration activated‐sludge process
Authors: Yang P. Y. , Thavinpipatkul Amnuay 
Published: December 2004

AbstractThe stability of the model of a completely mixed activated‐sludge process holding the recycle sludge concentration, XR, as a system constant subjected to pH, temperature, potassium cyanide, and phenol shock loading was investigated. Soft‐drink bottling wastewater was used and maintained at 1000 mg/liter chemical oxygen demand (COD). The hydraulic ratio and recycle sludge concentration were maintained at 0.3 and 7000 mg/liter, respectively. An initial dilution rate of ¼ hr−1 was maintained for pH and temperature shock loading, with ¼ and ⅛ hr−1 for KCN shock loading and ¼, ⅛, and \documentclass{article}\pagestyle{empty}\begin{document}$\frac{1}{16}$\end{document} hr−1 for phenol shock loading. It was found that the present system could handle pH shock loading as low as 4.0 and as high as 10.4 without any serious disruption of biological solid concentration and filtrate COD. At pH 4.0 shock loading, filamentous organisms were predominant. Temperature shock loading could be handled from 23 to 36°C without any leakage of effluent filtrate COD. At 46°C temperature shock, a 14 hr period was required to recuperate to the new steady state and provided only 85% of COD removal efficiency. For KCN (50 mg/liger) and phenol (85 mg/liter) shock loading, the dilution rates should be lower than \documentclass{article}\pagestyle{empty}\begin{document}$\frac{1}{16}$\end{document} hr−1 in order to shorten the transient period and improve the effluent quality. Biological kinetic constants included cell yield value, maximum growth rate, and the saturation constant, which was varied with the qualitative shock applied.
Production of citric acid in batch culture
Authors: Kristiansen B. , Sinclair C. G. 
Published: December 2004

AbstractWork has been carried out on the production of citric acid in batch culture using Aspergillus foetidus. It is shown that the dry weight increases throughout the fermentation. The supply of nitrogen is exhausted early and the subsequent increase in dry weight is due to accumulation of carbon by the cells. It appears that the exhaustion of nitrogen is a necessary prerequisite for the production of citric acid, which is produced by carbon‐storing cells. The pH history in the early part of the fermentation did not affect the final yields.
Solid‐state cultivation of Chaetomium cellulolyticum on alkali‐pretreated sawdust
Authors: Pamment N. , Robinson C. W. , Hilton J. , Moo‐Young M. 
Published: December 2004

AbstractSolid‐state fermentations (78% initial moisture content) of alkali‐pretreated Eastern Hard Maple sawdust were conducted in tray and tumble fermentors using chaetomium cellulolyticum. Crude protein content of the solids rose from 0.9 to 11% in the tray fermentor and 8% in the tumble fermentor in 20 days. These levels were almost equal to those achieved in corresponding slurry‐state fermentations (1–5% (w/v)) of the same substrate. Specific growth rates were two to four times lower in the solid‐state fermentors but this was offset by their greater solids‐handling capacity: the rate of protein production per unit volume of fermentation mixture was comparable to that of the 5% (w/v) slurry and two to three times higher than that of the 1% (w/v) slurry.
Procedure for the simultaneous large‐scale isolation of pullulanase and 1,4‐α‐glucan phosphorylase from Klebsiella pneumoniae involving liquid–liquid separations
Authors: Hustedt H. , Kroner K. H. , Stach W. , Kula M.‐R. 
Published: December 2004

AbstractA procedure for the simultaneous large‐scale isolation of pullulanase and 1,4‐alpha;‐glucan phosphorylase from Klebsiella pneumoniae is described. The pullulanase is solubilized from the cell wall by cholate treatment; cells and cell debris are removed by partition in a poly(ethylene glycol) (PEG)‐dextran two‐phase system and from the upper (PEG) phase of this system the pullulanase is isolated by ultrafiltration and precipitation with N‐cetyl,N‐,N‐,N‐trimethyl ammonium bromide to a purity of about 80% with a yield of 70%. The preparations are free of α‐amylase activity. The cell containing dextran‐rich phase is passed through a Manton‐Gaulin homogenizer. Then the phosphorylase is separated from the cell debris by partition in a second PEG‐dextran system. From the top phase of this system the phosphorylase is isolated by distribution in a PEG‐salt two‐phase system followed by batch adsorption on carboxymethyl‐Sephadex in a yield of 55%, a purity of around 90%, and nearly free of glycosyltransferase activity. All steps in the isolation of the two enzymes can be performed easily in a large scale.
Affinity chromatography of endoglucanase of Trichoderma viride by concanavalin A–agarose
Authors: Gong Cheng‐Shung , Chen Li Fu , Tsao George T. 
Published: December 2004

AbstractEndoglucanase (Cx cellulase) and cellobiase are often cross‐contaminated in separation procedures by ion‐exchange chromatography such as DEAE‐cellulose. By using concanavalin A (Con A)–agarose chromatography, Cx cellulase and cellobiase from Trichoderma viride can be separated. Cx cellulase showed affinity toward Con A, indicating a glycoprotein containing α‐D‐mannopyransyl and α‐D‐glucopyranosyl end groups or internal 2‐O‐D‐mannopyranosyl residues in sugar moieties. This method provides a way to estimate the quantities of Cx enzyme produced by T. viride and possibly by other organisms.