bluuebunny/crossref_metadata_2025_split huggingface dataset:
The nad‐dependent alcohol dehydrogenase of methylotrophic yeasts – an electrophoretic study (i)
Authors: Steudel A. , Nitzsche C. 
Published: December 2004

AbstractThe occurence of multiple forms of alcohol dehydrogenase (ADH) in methylotrophic yeasts is known from the literture. But no systematic work has been done to characterize these enzymes in detail. The aim of this work was to establish a suitable electrophoretic method for visualization of the ADH‐patterns of these organisms. It was found that the recovery of the enzyme activity during polyacrylamide gel electrophoresis (PAGE) depends on the composition of the gel buffer. The ADH of five different methylotrophic yeasts from the genera Candida, Pichia and Hansenula were analyzed. Every investigated organism shows rather complex ADH‐patterns.
Glucose influenced degradation of α‐santonin in pseudomonas sp. strain S (ATCC 43388)
Authors: Sangodkar U. M. X. , Mavinkubve S. 
Published: December 2004

AbstractPseudomonas sp., strain S ATCC 43 388 utilizes α‐santonin by inducible enzyme system measurable by oxygen uptake. Cells grown on acetate or benzoate show negligible oxygen consumption with α‐santonin. However, glucose grown cells show evidence of a rapid induction of santonin utilizing enzyme system indicating the implication of glucose or its metabolites in the regulation of degradation of santonin. As a consequence, growth of strain S on mixtures of glucose and α‐santonin occurs at rates higher than on either of the substrates alone. Mutants with lesion in the glucose metabolism, independent of α‐santonin degradation, fail to exhibit higher growth rates with the binary substrates. The results infer simultaneous metabolism of substrates.
Use of membrane operation for refining gibberellinic acid
Authors: Leonhardt H. ‐W. , Paul D. 
Published: December 2004

AbstractSynthetic membranes are increasingly used in biotechnology. The possibilities of influencing the performance by membrane operation and changing the performance by physical modification were discussed. With cellulose‐2,5‐acetate membranes it was shown that the modification leads to an increase in the concentration of gibberellinic acid.
Protein enrichment in plant by fusaria
Authors: Weichert D. , Zakordonets L. , Klappach G. , Charkevitch E. , Koval E. Z. 
Published: December 2004

AbstractFive micro fungi of the type Fusaria were investigated for the bioconversion of agricultural piant wastes. One strain was favoured for protein enrichment in heat‐pretreated straw, also improving digestibility in the fodder produced. The influence of the chitin content in the fodder was studied, and for calculating raw‐protein from the organic nitrogen content an additional factor of 0.92 was proposed to the known factor of 6.25. For the application of Fusaria strains in bioconversion processes a prognosis a prognosis was offered.
Production of Lipase by Yarrowia lipolytica, I. Lipases from Yeasts (Review)
Authors: Hadeball W. 
Published: December 2004

AbstractIn this paper a review is given about the most important lipase‐producing yeasts as well as the yield of lipase production. In order to find out the optimal conditions for lipase production by yeasts, it is necessary to investigate the influence of the main factors affecting lipase synthesis such as carbon and nitrogen sources, activators and inhibitors, interface‐affecting agents, temperature, pH and inoculum. Besides the yield of lipase as an efficiency factor of fermentation and the substrate specificity of lipase, playing an important role in applications, are described.
Homocitrate production by a lysine‐requiring pichia guilliermondii mutant
Authors: Schmidt H. , Bode R. , Birnbaum D. 
Published: December 2004

AbstractMutants of Pichia guilliermondii were isolated that lacked homoaconitate hydratase (lys4), homoisocitrate dehydrogenase (lys10) or α‐aminoadipate reductase (lys2) and were able to excrete homocitrate into the culture medium. The effects of incubation time and lysine concentration in the medium on the excretion of homocitrate were examined. In the presence of 600 mg of L‐lysine/1 in a minimum salt medium P. guilliermondii G75 (lys2) produced about 280 mg homocitrate/1 during 48 h of growth. A simple procedure to isolate homocitrate from the medium is described.
Phytic acid content reduction in canola meal by various microorganisms in a solid state fermentation process
Authors: Nair V. C. , Duvnjak Z. 
Published: December 2004

AbstractSolid state fermentation of canola meal has been carried out for the reduction of its phytic acid content using the following microorganisms: Rhizopus oligosporus NRRL 2990, Aspergillus niger NRC 5765 and NRC 401 121, Aspergillus ficuum NRRL 3135 and a wild Saccharomyces cerevisiae strain.The results showed that all these microorganisms can be used for the reduction of the phytic acid content in the tested material. A. ficuum which completely hydrolyzed the phytic acid in 48 hours was the most efficient.Buffered systems, aeration and an increase in inoculum concentration caused faster and higher reduction of phytic acid content in canola meal.
Some kinetic studies on ribonucleosides degradation by extracts of penicillium citrinum
Authors: Allam A. M. , Elzainy T. A. , Elsayed M. A. , Elshafei A. M. 
Published: December 2004

AbstractCell‐free extracts of 3–4 days old mats of nitrate‐grown Penicillium citrinum catalyze the hydrolytic cleavage of the N‐glycosidic bonds of inosine, guanosine and adenosine optimally at pH 4, 0.1 M citrate buffer. The same extracts catalyze the hydrolytic deamination of cytidine at a maximum rate in 0.08 M Tris‐acetate buffer pH 6.5, 40°C and 50°C were the most suitable degrees for purine nucleoside hydrolysis and cytidine deamination, respectively. The incubation of the extracts at 60°C, in the absence of cytidine caused a loss in the deaminating activity, while freezing and thawing had no effect on both activities. The deaminating activity seems to be cytidine specific as neither cytosine, adenine, adenosine nor guanosine could be deaminated. Uridine competively inhibited this activity, while ammonia had no effect. The apparent Km value of this enzyme for cytidine was 1.57×10−3M and its Ki value for uridine was 7.8×10−3M. The apparent Km values of the N‐glycosidic bond cleaving enzyme for inosine, guanosine and adenosine were 13.3, 14.2 and 20×10−3 M, respectively.
The NAD‐dependent alcohol dehydrogenase (ADH) of hansenula polymorpha cbs 4732 – an electrophoretic study (II)
Authors: Steudel A. , Nitzsche C. 
Published: December 2004

AbstractUsing gradient polyacrylamide gel electrophoresis (gradient between 10–20%) we were able to show up to six clearly distinguishable ADH‐bands in Hansenula polymorpha CBS 4732. In contrast to commercial ADH from Saccharomyces cerevisiae the ADH‐forms of Hansenula polymorpha CBS 4732 have a much broader substrate specificity. Furthermore, the occurence of secondary alcohol dehydrogenases and of an aromatic alcohol dehydrogenase could be demonstrated.
Enzymatic production of indolepyruvate and some of its methyl and fluoro‐derivatives
Authors: Bode R. , Birnbaum D. 
Published: December 2004

AbstractUsing the tryptophan aminotransferase of the fodder yeast Candida maltosa the enzymatic production of indolepyruvate, and of analogues of indolepyruvate from tryptophan and methyl and fluoro‐derivatives of tryptophan was investigated. After the optimization of the reaction conditions such as pH, temperature, concentration of the cofactor and ratio between substrate and cosubstrate, a good yield of indolepyruvate (about 70%) and its derivatives (10–30%) was achieved. After isolation products were purified and crystallized.
Biotechnological aspects of antibody production in E. coli
Authors: Plückthun A. 
Published: December 2004

AbstractThe production of genetically engineered antibodies in Escherichia coli is now possible. The resulting fragments are completely functional and have antigen binding constants industinguishable from the natural antibody. This article summarizes the biochemical basis of this newly developed technology and the properties of the resulting fragments. It is likely that this technology will have an important role in antibody production for technical, medical and research uses. Screening of E. coli libraries may mount a challenge to traditional antibody production methods.
Calculating affinity constants of substrate mixtures in a chemostat
Authors: Bley Th. , Babel W. 
Published: December 2004

AbstractAn “oversimplified” method for calculating affinity constants in substrate mixtures is evaluated concerning its validity. It is shown that the real affinity to the mixture as determined by using the correct method is always higher, i.e., leads to a lower affinity constant, as compared to the wrong method frequently used.
Some studies on Nigerian palm wine with special reference to yeasts
Authors: Enwefa C. , Uwajeh R. , Oduh M. 
Published: December 2004

AbstractThe identification and enumeration of yeasts and the effect of chemical preservatives on the yeast load in Nigerian palm wine have been studied. Yeast found largely belong to the genus Saccharomyces. Other genera found were Candida, Endomycopsis, Hansenula, Kloeckera, Pichia, Saccharomycoides and Schizosaccharomyces. The viable yeast count ranged from 0.5 × 107 cfu/ml to 4.2 × 109 in both fresh Elaeis and Raphia spp. of palms. Yeasts in palm wine were least sensitive to sodium nitrate and most sensitive to sodium benzoate. The addition of these two chemical preservatives amongst others reduced the yeast count to 3.2 × 108 (in Raphia sp.), and 4.1 × 109 (in Elaeis sp.) with 0.025% sodium nitrate and 1.2 × 106 (in Raphia sp.) and 1.9 × 107 (in Elaeis sp.) with 0.1% sodium benzoate. The values of the yeast count in bottled and fresh palm wine were between 1.3 × 103 cfu/ml to 9.8 × 106 and 0.5 × 107 to 4.2 × 109, respectively. Maximum values of actual dry and theoretical yeast weights were 1.09 and 42 mg/ml, respectively.
Effect of formaldehyde on the level of cytochrome c in methylotrophic yeasts
Authors: Dercová K. , Augustín J. , Pekniková D. 
Published: December 2004

AbstractThe effect of formaldehyde on the cytochrome system of the methylotrophic yeasts Candida tropicalis, Candida boidinii, Candida methylica, Hansenula capsulata, Hansenula polymorpha, Pichia pastoris and nonmethylotrophic yeasts Saccharomyces cerevisiae was studied. In the investigated concentration range of 0.58 – 2.5 mol · 1−1, formaldehyde decreases the level of the reduced cytochrome c in the above‐mentioned microorganisms. The kinetics of the change in the reduced cytochrome c content has two phases: a phase of slow decrease and a phase of complete disappearance of the reduced cytochrome c in the cells. The duration of the first phase shortens with increasing concentrations of formaldehyde.
Effect of calcium carbonate on conversion of starch to ethanol by Schwanniomyces castellii
Authors: Mok K. L. , Duvnjak Z. 
Published: December 2004

AbstractConversion of starch to ethanol without its prior hydrolysis is of special interest in the treatment of the starch containing waste‐waters. In this work the effect of calcium carbonate on the growth and ethanol production from soluble starch by Schwanniomyces castellii NRC 2676 was studied. When the medium was supplemented with 0.1% calcium carbonate the biomass yield and the total starch consumption were increased by 20% and 22%, respectively, while the ethanol yield decreased for 28% in comparison with the control. The rate of biomass production, measured for the period of time between 0 and 24 h, was the highest in the medium with 0.06% calcium carbonate while the rates of ethanol production and starch consumption decreased with and increase in the concentration of that salt; the media with 0.5% and 0.7% calcium carbonate had 3.5 and 5.5 times lower ethanol production rates, and 2.3 and 3.8 times lower rates of starch consumption than the control medium which was not supplemented with calcium carbonate, respectively. The obtained results also showed that the percentage of starch consumed was higher in the media supplemented with calcium carbonate than in the control.Empirical mathematical expressions are given for the relationship of the biomass and ethanol yields to the concentration of calcium carbonate in the medium.
Regulation of xylanase activity in cellulomonas sp. IIbc
Authors: Rodriguez H. , Alea F. 
Published: December 2004

AbstractThe regulation mechanism governing the xylanolytic activity in the strain Cellulomonas sp. IIbc was studied. High levels of activity were detected during the cultivation on cellulose as the only carbon source. No activity was produced with glucose, xylose or cellobiose cultures, but in the last one, the synthesis was de‐repressed when the sugar concentration dropped to 0.2%. The activity was not inhibited by glucose, cellobiose and xylose up to 1% concentration.A basal constitutive synthesis was detected in nutrient broth cultures. At the same time, xylose and cellobiose acted as inducers of the xylanase activity.
Isolation and characterization of thermophilic bacteria from natural and artificial habitats
Authors: Zentgraf B. , Hedlich R. , Gwenner C. , Uyen N. V. , Thao N. N. 
Published: December 2004

AbstractSeveral thermophilic Bacillus Strains were isolated from natural as well as artificial habitats. They grow optimally on a carbohydrate‐containing medium at a temperature of 65 to 68°C and a pH value of 6 to 7 under aerobic conditions. They utilize glucose, sucrose and sodium acetate as carbon and energy sources. They can be differentiated by acid formation and composition of intracellular fatty acid fraction as well as growth on xylose, lactose, starch, cellobiose, ribose and galactose.
Description of the delayed microbial growth by an extended logistic equation
Authors: Wolf K.‐H. , Venus J. 
Published: December 2004

AbstractLogistic equations are suitable for describing microbial growth. By means of VERHULST'S logistic equation, the adaptation to sigmoid‐shaped curves of growth improves with a falling ratio Cxo/Cx, max < 0.2, if there is no lag‐phase. The known logistic equations do not take into account any lag‐phase behaviour, so that noticeable deviations in the model adaptation result in this range. Therefore, an extended logistic equation of rate is proposed by which any occuring lag‐time is expressed by a 1st‐order lag‐term. The corresponding time law allows a very good adaptation of curves of delayed growth behaviour, and changes into VERHULST'S logistic equation for a lag‐time tL = 0. Application is facilitated by instructions for the numerical determination.
Coexistence of competing microbial species in a chemostat where one population feeds on another
Authors: Lenbury Y. , Siengsanan M. 
Published: December 2004

AbstractIn this paper, we consider a model for a chemostat in which two microbial species compete for a single rate‐limiting nutrient, while one of the species feeds on another. Under certain simplifying hypotheses, such a chemostat can be described by a system of three nonlinear ordinary differential equations. A theoretical study is conducted to characterize the possible types of solutions. A limit cycle solution was obtained for some parametric values of the system indicating that coexistence of the two species is possible in a significant range of the operating parameters.
Thermophilic bacteria from spent liquor of pulp mills
Authors: Zentgraf B. , Gwenner C. , Hedlich R. 
Published: December 2004

AbstractA thermophilic bacterial mixed culture was isolated from spent liquor of pulp mills, using a chemostat under aerobic conditions. It consists of two components belonging to genus Bacillus. The thermophilic Bacilli were cultivated aerobically and continuously at 67–70°C and pH 6.8–7, rising the percentage of spent liquor in stages. The dilution rate ranged from 0.2 to 0.33 h−1 during the experiments. The composition of the cell mass produced was analyzed.
Regulation of proteinase synthesis in Lactococcus lactis
Authors: Laan H. , Bolhuis H. , Poolman B. , Abee T. , Konings W. N. 
Published: December 2004

AbstractThe synthesis of extracellular serine proteinase of Lactococcus lactis was studied during the growth in a batch and a continuous culture on chemically defined media. In a batch culture the proteinase synthesis started during the exponential phase of growth and the highest proteinase concentrations were found at the end of the exponential and beginning of the stationary phase of growth. During the growth in a lactose‐limited chemostat with amino acids as the sole source of nitrogen, the specific rate of proteinase synthesis was maximal at a μof 0.23 h−1. At higher growth rates the proteinase productin declined. The proteinase synthesis was dependent on the amino acid sources in the medium. In batch cultures of L. lactis grown on a chemically defined medium with amino acids, the proteinase production was increased four‐fold compared to media containing casein or a tryptic digest of casein as the sole source of nitrogen. The inhibition of the rate of proteinase synthesis by casein and peptides was also observed during the growth in a chemostat. The addition of the dipeptide leucylproline (final concentration of 100 μM) to a lactose‐limited continuous culture during the steady state (D = 0.23 h−1) resulted in a transient inhibition of the rate of proteinase synthesis. This suggested that exogenously supplied peptides control the regulation of proteinase synthesis of L. lactis.
The recovery of the hepatitis B virus surface antigen (HBsAg) from a recombinant P. pastoris strain disruption and precipitation studies
Authors: Páez R. , Agraz A. , Herrera L. 
Published: December 2004

AbstractCell disruption studies for the extraction of HBsAg from a recombinant P. pastoris strain (r‐HBsAg) were done using a bead mill disintegrator. Three sequential passages (4 min retention time each) were enough to disrupt the cells and extract most of the r‐HBsAg and soluble proteins. An acid precipitation step was performed just after cell disruption to precipitate proteins together with the cell debris. Different precipitation pH values (2.5 to 6.0) were investigated. A pH value of 4.2 was selected as a compromise between recovery and improvement of specific activity. A 6 to 8‐fold enhancement of the specific activity was obtained, having a r‐HBsAg overall yield of about 80%. The influencing presence of a chaotropic salt (potassium thiocyanate) during the acid precipitation step was also studied.
Influence of carbon and nitrogen sources on the lipid accumulation and arachidonic acid production by Mortierella alpina
Authors: Stredanská S. , Šajbidor J. 
Published: December 2004

AbstractCarbon and nitrogen influence the lipid accumulation and arachidonic acid production by Mortierella alpina CCF 185 cultivated at 28°C for 7 days on a rotary shaker. The fungus grown with glucose, starch or dextrin as the carbon source produced satisfactory amounts of lipid and arachidonic acid. The maximum arachidonic acid values were obtained on media with yeast extract or NaNO3 as the nitrogen source. The C/N ratio of 40:1 resulted in the highest yields of lipid and arachidonic acid with different amounts of NaNO3 concentration.
Optimization of sorbose production from sorbitol by Gluconobacter oxydans
Authors: Rosenberg M. , Švitel J. , Rosenbergová I. , Šturdík E. 
Published: December 2004

AbstractThe basic parameters were studied influencing the conversion of orbitol to sorbose by Gluconobacter oxydans(industrial strain from FARMAKON Co., Czechoslovakia). The most effective conversion in the stationary phase was reached at pH 5.0, no inhibitory effect of sorbitol in a concentration ranging from 20 to 200 g/l and a minimum inhibitory effect of the sorbose concentration up to 200 g/l were observed. According to the optimum conditions mentioned above the optimized course of the fed‐batch cultivation was proposed. The final concentration of sorbose of 410 g/l was reached after 36 hours.
The application of a new type of sintered glass carriers for the cultivation of anchorage‐dependent mammalian cells
Authors: Rzeski W. , Kandefer‐Szerszeń M. , Kaczor J. , Dawidowicz A. L. , Wozowicz A. 
Published: December 2004

AbstractCylinder‐shaped sintered glass carriers were successfully used for immobilizing and cultivating cells of murine line L929. The process has been performed in a fixed‐bed bioreactor (working volume of 150 ml) with perfusion and aeration of the medium (total volume of 3.5 l). The maximum cell density of 1.23 × 107cells/ml was achieved when the basal medium (MEM + 10% bovine serum) was enriched with glucose (up to 2 g/l) and L‐glutamine (up to 4 mM). The carriers have proved to be nontoxic, mechanically stable and reusable.
Oxygen mass transfer and gas holdup in a bubble column bioreactor with biosynthesis liquids
Authors: Gavrilescu M. , Roman R. V. 
Published: December 2004

AbstractThe influence of the rheology of some antibiotic biosynthesis liquids produced by Streptomyces aureofaciens, Nocardia mediterranei and Penicillium chrysogenum on the volumetric liquid phase oxygen transfer coefficient, kLa, and gas holdup, εG, together with the influence of superficial gas velocity, were studied in a bubble column bioreactor, using samples of fermentation liquids taken from industrial stirred tank fermenters, at 30‐hour intervals during fermentation batch.The results were compared to those of previous studies from literature on non‐Newtonian homogeneous fluids, such as CMC‐Na, xanthan and starch solutions, respectively.In the heterogeneous broths, εG and kLa decreased with increasing apparent viscosity of the broth and increased with increasing superficial velocity.The experimental data were correlated using non‐linear regression

with correlation coefficients above 0.85.
Characteristics of phytase produced by Aspergillus carbonarius NRC 401121 in canola meal
Authors: Al‐Asheh S. , Duvnjak Z. 
Published: December 2004

AbstractAspergillus carbonarius NRC 401121 phytase was produced on canola meal in a solid‐state fermentation process. A Km value of 0.345 mM and a vmax of 0.81 units were determined for sodium phytate. The optimum pH and temperature were 4.7 and 53°C, respectively. Activation of the enzyme occurred when it was preincubated at higher temperatures for a period of time. The energy of activation, the entropy and the enthalpy changes were evaluated to be 7,800 cal/mole, 74 cal/(mole · K) and 24,000 cal/mole for this enzyme, respectively.The effect of time and the extractant: solid state culture ratio upon the single step extraction of phytase from a solid‐state culture were evaluated.Mathematical correlations which fit the experimental data reasonably well were proposed for some of the studied processes.
Influence of the casing on the microflora of compost colonized by Agaricus bisporus
Authors: Gillmann L. , Lebeault J. M. , Cochet N. 
Published: December 2004

AbstractThe role of the casing soil during mushroom cultivation was studied with respect to the composition of the microflora. The thermophilic bacteria became more numerous and the number of mesophiles was clearly enhanced. The casing soil had a protective action against antagonistic microflora. Interactions between the microflora and the mushroom were also studied.Moreover, lignocellulose degradation was evaluated by enzymatic measurements during cultivation and process, and was documented by an ultrastructural study.