bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wachstumskinetik von Aspergillus niger A.n./61 in einem festen Medium
Authors: Czajkowska D. , Ilnicka‐Olejniczak O. 
Published: December 2004

AbstractGrowth kinetics of Aspergillus niger strain A.n./61 on a solid medium containing beet pulp were examined.Solid state fermentation was carried out in laboratory microfermenter (aerated packed columns). During the experiments the CO2 evolution, protein biosynthesis, as well as cellulose and sucrose utilization were determined.It was found that CO2 evolution evidently increased in the logarithmic phase, together with the protein biosynthesis. Between 30–32 h of culture CO2 evolution and protein content in product were the greatest. Subsequently, CO2 evolution decreased.During 28 h of culture, cellulose was slightly utilized, the strain using mainly sucrose. Intense utilization of cellulose was paralleled by a drop in CO2 evolution.
Antiphytovirale Aktivität von Rhamnolipid aus Pseudomonas aeruginosa
Authors: Haferburg D. , Hommel R. , Kleber H.‐P. , Kluge S. , Schuster G. , Zschiegner H.‐J. 
Published: December 2004

AbstractA rhamnolipid released by Pseudomonas aeruginosa 196 Aa into the culture medium reduced the number of local lesions induced by tobacco mosaic virus on leaves of the hypersensitive host Nicotiana glutinosa L. by up to 90%. The content of potato virus X in the systemically infected host Nicotiana tabacum L. ‘Samsun’ is decreased in inoculated as well as in secondarily infected leaves by up to 50%. In a smaller degree red clover mottle virus is influenced in the systemic host Pisum sativumconvar.speciosum (Dierb.) Alef ‘Nadja’.
Cultivation of measles virus on bovine kidney cells: Comparative study on viral yield
Authors: Eghafona N. O. , Ezeokoli C. D. , Ahmad A. A. , Emejuaiwe S. O. , Odama L. E. 
Published: December 2004

AbstractThe present investigation sought the use of Bovine Kidney Cells (BKC) which is a readily available substrate for the cultivation and isolation of measles virus. Results showed that measles virus grew well on BKC, showing identical cytopathologic effect (CPE) of syncytial and giant cell formation also noted for Vero cells. However, the growth on Vero cells was faster indicating a better sensitivity to the measles virus than BKC. The virus replicated and produced CPE in both confluent monolayer and trypsin dispersed cultures. The ability of the virus to form CPE was faster in trypsin‐dispersed cells than confluent monolayers.The viral yield in Vero‐ and BK‐cells were compared to assess any difference by analysis of variance. The F‐value of 0.824 with degree of freedom 1.34 showed no significant difference at any reasonable confidence interval.
Biochemical studies on the effect of various carbon sources on growth, nitrogen fixtion, and main cellular constituents of azotobacter vinelandii, strain IV grown under various cultivation conditions
Authors: Shawky B. T. , Ghali Y. , Ahmed F. A. , Kahil T. 
Published: December 2004

AbstractThe accessibility of different carbon compounds to Azotobacter vinelandii and the productivity of nitrogen fixation were studied under static and shaking culture conditions. The nature of the carbon source applied was found to affect the yield of bacterial mass and nitrogen metabolism of the tested organism. On the basis of the efficiency of dinitrogen fixation and the yield efficiency ratio it was obvious that (sucrose + mannitol) as a source of carbon is optimum for both growth and dinitrogen fixation by A. vinelandii grown under static and shaking culture conditions. Furthermore, it was found that the highest crude protein efficiency ratio (14.6) and total carbohydrates efficiency ratio (4.3) were obtained with (sucrose + mannitol) as energy source for this organism under shaking culture condition. The experimental organism is able to convert the soluble nitrogenus substances present in molasses into more complex protein as well as to utilize the molasses as a source of energy for the fixtion of atmospheric nitrogen. The tested organism was unable to utilize sodium salicylate as the sole source of carbon.
Wechselwirkungen zwischen seltenen Erdmetallen und Mikroorganismen
Authors: Bullmann M. , Iske U. , Glombitza F. , Dittrich B. 
Published: December 2004

AbstractIn recent years there have been a lot of works on the accumulation and removal of heavy metals from aqueous solutions and industrial waste waters by different kinds of microorganisms. A variety of microorganisms are known to be tolerant to mercury, copper, chromium, silver, cadmium etc., or to have a high accumulation capacity for these elements.But nothing is known about the interactions between microorganisms and REE*‐ions in aqueous solutions.The objectives of our experiments were to determine the ability of various microorganisms to accumulate REE and to determine what possible effects, in terms of growth, different REE‐ion concentrations may have on the bacteria cultures.Experiments on the accumulation of La and Pr by a freeze dried bacteria mixed culture, carried out with model solutions, showed that the accumulation process is completed few minutes after contact. The uptake is independent on pH‐value and temperature and amounts up to 63 mg REE/g biomass in both cases.A gram+ bacterium spec., isolated from an industrial waste water, accumulates large quantities of REE in dependence on the pre‐treatment of the cells, e.g. in the case of resting or freeze dried cells up to 100 mg/g biomass and in the case of heat treated cells up to 40 mg/l.
Gas chromatographic analysis of free fatty acids. Part 1. Principles and methodic variants
Authors: Pörschmann J. , Welsch T. , Pörschmann S. 
Published: December 2004

AbstractProceeding from a literature search the problems faced by the today's gas chromatographer concerned with analysis of free fatty acids are summarized. In terms of column technology self‐made OV‐1/FFAP mixed phase capillary columns are well suited for adequate tailing — free elution of these polar molecules. Whereas fatty acids having two and more carbon atoms can be analyzed in an underivatized state on acidic capillary columns, the involving of formic acid and dicarboxylic acids cells for deactivation procedures.
Einfluß ausgewählter Nährsalzionen auf die Wachstumskinetik des methanotrophen Bakteriums gb 25
Authors: Wendlandt K.‐D. , Jechorek M. , Brühl E. , Wittig H. , Osokina N. V. , Lalov V. V. 
Published: December 2004

AbstractThe influence of different concentrations of magnesium, potassium, phosphorus and copper on the growth kinetics of the methanotrophic bacterium GB 25 was investigated. Diverse inhibition models were used for the mathematical description of the results. On the basis of these model equations the optimal concentrations of the investigated ions were derived. Copper causes the greatest inhibition, on the contrary, potassium practically does not inhibit the growth of bacterium GB 25.
Hydrolysis of whey by kluyveromyces bulgaricus cells immobilized in stabilized alginate and in chitosan beads
Authors: Decleire M. , De Cat W. , Van Huynh N. , Motte J. C. 
Published: December 2004

AbstractKluyveromyces bulgaricus cells were immobilized in matrices resisting to complexing anions. Yeast entrapped in alginate stabilized by polyethylenimine and glutaraldehyde were unable to hydrolyse whey owing to the inactivation of β‐galactosidase by the stabilizing agents. Chitosan was resistant to whey medium but decreased the yeast hydrolyzing capacity by 15% with respect to alginate. The hydrolysis rate was found to be unchanged for 37 days at 21–25°C.
A kLa identification technique for a dynamic model of the coupled system: Air‐lift fermenter — oxygen probes
Authors: Gluszoz P. , Starzak M. , Michalski H. 
Published: December 2004

AbstractThe time delay of oxygen probe response to the signal from a fermenter makes identification of the volumetric oxygen transfer coefficient kLa by the dynamic method more complicated. A coupled model involving the transient‐state oxygen balance of the fermenter together with the dynamic model of the oxygen probe must be then formulated, solved and identified.In this paper two simple models of air‐lift loop fermenters have been proposed and a coupled mathematical model of the fermenter – oxygen probe system has been developed. The identification procedure was used to estimate kLa values in the fermenter with internal circulation flow on the basis of experimental measurements. A comparison of evaluated and experimental indications of the probes placed at various heights of the column proves that the model presented gives a possibility of the first‐step approximation of kLa in loop fermenters.
Enzyme overproduction: Principle and application
Authors: Tripathi G. 
Published: December 2004

AbstractThe rapprochement between gene physiology and protein chemistry proffered a wishful manipulation or programming of biological blueprint which we now know as recombinant DNA technology. Its premises are very many and ends are manifold. Until rather recently, the recombinant DNA technique could conceive the idea of engineering enzyme molecules by cloning and selection of the gene in question for enzyme production. At least, in principle, the process is too simple but its underlying mechanism is rather much stringent. Various experimental paradigms have been brought to work for production of enzyme at will by introducing a given gene into a high yielding system of microorganisms. It facilitates overproduction of enzymes of interest which can be implicated in several important industrial, biomedical, and environmental processes at a large scale. Such approaches of enzymes made‐to‐application have already started asserting tremendously in doing their appropriate jobs at the level of molecular interactions. A rapid progress in this important and interesting area of biocatalytic manipulation will certainly achieve the goal of biocatalysis‐made‐to‐order by altering kinetic and thermodynamic components of enzyme molecules.
β‐Glucosidase production by Trichoderma reesei QM9414 on wheat straw. Location and some kinetic features
Authors: Acebal C. , Arche R. , Castillon M. P. , Estrada P. , Romero D. 
Published: December 2004

AbstractIn this paper we studied the conditions for the production of β‐glucosidase from T. reesei QM9414 in batch cultures using milled and sieved wheat straw as sole carbon source. High β‐glucosidase production in the presence of wheat straw, a more realistic substrate than commercial cellulose, was obtained.The influence of particle size of wheat straw on β‐glucosidase production in cell‐free, cell and cell‐wall extracts was studied. The particle size of wheat straw notably influenced enzyme production in cell and extramycelial extracts but it was less important with respect to the cell wall bound enzyme.β‐glucosidase production was studied along of the fermentation. The results suggest a close relation between β‐glucosidase from cell extract and extramycelial broth; geneticin levels of inhibition of β‐glucosidase biosynthesis in both fractions were similar, a fact that suggests a common origin for the enzyme.Kinetic parameters for β‐glucosidase from cell free and cell extracts were Vmax = 0.28 μmol/min/mg, KM = 0.91 mM and Vmax = 0.095 μmol/min/mg, KM = 0.39 mM respectively. Kinetic parameters for β‐glucosidase from cell‐wall could not be calculated because experimental data did not fit the different monosubstrate equations.
Tween 80 and proteose peptone effect on cellulase production
Authors: Hung B. R. , Lara L. , Patrón M. A. , Clappes S. , Ugarova N. N. , Bechstedt W. 
Published: December 2004

AbstractTween 80 and proteose peptone effect on cellulase production with Trichoderma spec. was studied. Sugar cane pith was used in the medium as carbon source. Tween 80 increases cellulase production while proteose peptone has influence on enzyme adsorption. There is a combined effect on cellulase production between them.
Isolation and some properties of two extracellular β‐glucosidases from Trichosporon adeninovorans
Authors: Büttner R. , Bode R. , Scheidt A. , Birnbaum D. 
Published: December 2004

AbstractThe yeast Trichosporon adeninovorans secretes two multiple forms of β‐glucosidase at a high rate if grown in a medium containing cellobiose. Following mutagenesis a mutant strain resistant to 2‐deoxy‐D‐glucose was selected. This strain produced more β‐glucosidase activity and had acquired a strong resistance against repression by glucose. The β‐glucosidases were separated one from each other by chromatography on hydroxylapatite and by gel filtration. Both enzymes have similar properties. The optimal temperature for their activity was 60 to 63°C and the enzymes displayed highest activity at pH of 4.5. The molecular weight of β‐glucosidase I was found to be 570,000 and that for β‐glucosidase II was 525,000. The Km value for cellobiose was determined to be 4.1 mM for β‐glucosidase I and 3.0 mM for β‐glucosidase II.
L‐Lysine production by auxotrophic mutants of Arthrobacter globiformis
Authors: Samanta T. K. , Das Y. , Mondal S. , Chatterjee S. P. 
Published: December 2004

AbstractBy mutagenesis with N‐methyl N‐nitro‐N‐nitrosoguanidine, in two steps, a number of methionine plus threonine double auxotrophs have been isolated from a glutamate producing Arthrobacter globiformis, excreting L‐lysine in good amounts. For the three potent mutants tested the medium of WHITE was adjudged to be the best. Biotin, ammonium chloride and glucose was found to be optimum at 5 μg l−1, 40 mM and 4% level, respectively. With such optimal C and N source, the strain MT 35 yielded 28.0 g lysine l−1 of medium in flask culture.
Naturwissenschaftliche Aspekte eines diffusiven Strohaufschusses mit verdünnter Alkalilauge
Authors: Mietz M. , Berg F. , Philipp B. , Paul D. , Jacopian V. 
Published: December 2004

AbstractChanges in chemical composition and morphology of wheat straw during a 5‐step treatment with delute aqueous sodium hydroxide of increasing (step 1 to 3) and then decreasing (step 4 and 5) NaOH concentration are described varying straw pretreatment, maximum NaOH concentration and total time of contact between straw and lye. These structural changes are correlated to increase in swelling, in‐vitro degradability by cellulase and digestibility as revealed by feeding tests with sheep. Results are discussed on the basis of the processes of swelling, delignification and pentosan extraction, and the technological advantages of this multi‐step treatment for enhancing the nutritional value of straw are discussed in comparison to a one‐step treatment with subsequent lye‐removal by pressing.
Zur biotechnologischen Relevanz von Regulationsvorgängen des mikrobiellen Sekundärstoffwechsels
Authors: Bormann E. J. 
Published: December 2004

AbstractAlthough the regulation of microbial secondary metabolism belongs to the important objects of actual investigations the results and knowledges are used rather poorly in industrial fermentations. This situation arises from the discrepancy between the economically driven development of the know how as soon as possible contrary to the more slow progress of profound examination of the complicated network of secondary metabolism. Nevertheless some well known principles of metabolic regulation, e.g. catabolite repression or resistance against products or metabolites are considered in fermentation processes by means of suitable substrate application as well as improvement of high yield strains. Both aspects are discussed with respect to examples of fermentations of β‐lactams, polyketides and glycopeptides.
A reduced specific ethanol‐forming performance of yeast at high biomass concentrations as a result of a changed ethanol‐tolerance behaviour of the cells under condition of limitation I. A theoretical treatment
Authors: Richter K. 
Published: December 2004

AbstractThe loss of fermentative activity of yeast cells, observed in continuous fermentation experiments at increasing biomass concentration is explained by the assumption that the ethanol‐tolerance behaviour of the microorganisms changes if a growth‐stabilizing factor limitation is present. A mathematical specification of the relationships existing in this context is given and an improved steady‐state productivity model of ethanol production is derived.
A reduced specific ethanol‐forming performance of yeast at high biomass concentrations as a result of a changed ethanol‐tolerance behaviour of the cells under condition of limitation. II. Proving the effect in high‐flow rate fermentations with saccharomyces cerevisiae Sc 5
Authors: Richter K. , Becker U. , Meyer D. 
Published: December 2004

AbstractIn growth‐factor limited fermentations carried out in continuous high‐flow rate fermenters the relationship existing between the specific ethanol formation rate and the ethanol concentration was found to change its characteristics from a linear function into a nonlinear one at high biomass concentrations. The deviation from the linear inhibitory behaviour of the cells was the greater the more the biomass concentration increased.A very good correspondence between the experimentally found productivities of ethanol formation and its adequate values obtained by calculation could be attained by using an improved steady‐state productivity model, in which the variability of the function v = f(P) had been considered.
Characterization of biotechnological processes and products using high‐performance liquid chromatography (HPLC) IV. SEC, HIC, and IEC separations of proteins
Authors: Gey. M. , Thiem M. , Gruel H. 
Published: December 2004

AbstractProteins are separated by means of size‐exclusion (SEC), hydrophobic‐interaction (HIC) and ion‐exchange chromatography (IEC). Analytical and semipreparative HPLC glass columns are the basis of the chromatographic analyses.Using a short (100 × 3.8 mm i.d.) column packed with Si 200 Polyol standard of different molecular weights (ovalbumin, MW = 43 000; chymotrypsinogen A, MW = 25 000; ribonuclease, MW = 13 700 and contrycal, MW = 6512) could be distinguished.Basic proteins (e.g., chymotrypsinogen A, cytochrome C) are separated on aluminium oxide (Li‐Chrosorb Alox T) by cation‐exchange chromatography. Correlations between the retention times of proteins and their isoelectric points or the buffer concentration of the mobile phase are investigated.Furthermore, two examples of liquid chromatographic purification procedures for enzymes of biotechnological interest are demonstrated. One enzyme extract (thermostable protease) is separated by hydrophobic‐interaction chromatography, another one (β‐galactosidase from a thermophilic microorganism) is purified on a weakly basic anion‐exchange resin (pore size: 130 nm) based on a styrene‐divinylbenzene copolymer.
Flow cytometric determination of yeast sterol content
Authors: Müller S. , Schmidt A. 
Published: December 2004

AbstractA method for the flow cytometric determination of the unesterfied 3β‐hydroxysterol content in yeast populations by the fluorescence shifted macrolide nystatin in presented. Preliminary investigations of changing sterol content in aerobic and anaerobic batch cultivation revealed the technological usefullness of this information.
Macromixing characteristics of gas‐liquid jet loop reactors
Authors: Warnecke H.‐J. 
Published: December 2004

AbstractMeasurements of liquid macromixing characteristics are reported for a half industrial scaled jet loop reactor operating with air‐water mixtures. Based on a model of loop reactors with sections of different mixing behavior the single circulation dispersion coefficient can be split into its components caused by the riser and the downcomer. The dispersion coefficient of the riser is about 100 times greater than that of the downcomer. The addition of gas involves greater dispersions coefficients. The comparison of the mixing times of the JLR with those of stirred vessels leads to the conclusion that the JLR is equivalent or even superior to stirred vessels.
Lysine production by auxotrophic‐regulatory mutants of corynebacterium glutamicum
Authors: Plachý J. 
Published: December 2004

AbstractA mutant of Corynebacterium glutamicum dependent on homoserine and resistant both to S‐(2‐aminoethyl)‐L‐cysteine and lysine hydroxamate, cultivated under submerged conditions for 4 days in a medium containing sucrose, corn‐steep and pea nut meał hydrolyzate, accumulated 33.5 g/l lysine.
Infrared and antimicrobial studies on different lignins
Authors: Nada A. M. A. , El‐Diwany A. I. , Elshafei A. M. 
Published: December 2004

AbstractThe aim of this work is to study the IR spectra of the different lignins precipitated from the produced liquor of different pulping conditions of bagasse and cotton stalks, also to study their antimicrobial activities towards some bacteria and fungi.
Mathematical modelling of immobilized living yeast cell reactor for sugar bioconversion to ethanol
Authors: Jinescu G. , Lavric V. , Brǎgǎrea St. , Popescu M. 
Published: December 2004

AbstractIn the present work, a mathematical model was developed regarding the immobilized living yeast cell reactor for sugar bioconversion to ethanol. The model, composed of a system of ordinary differential equations (ODEs) enables the computation of the paramters involved in the steady state reactor behaviour. Comparing the values computed through the integration of this mathematical model with the experimental data, it has been shown its capacity to describe sufficiently accurate the steady state behaviour of the continuous fixed film bioconversion reactor.
Neuere Erkenntnisse zur Regulation des Sekundärstoffwechsels von Streptomyceten
Authors: Gräfe U. 
Published: December 2004

AbstractA survey is given summarizing recent insights into the causes of the genetic segregation of antibiotic‐producingStreptomycesstrains (plasmids, transposons, reiterated gene sequences, direct and inverted repeats). Referring to the classical regulatory models of prokaryotic operons, similar regulatory principles were shown to be involved in the secondary metabolism (pab‐gene ofS. griseus, brp‐gene ofS. hygroscopicus, afs B‐gene and A‐factor ofS. griseus) and the known features of its control by catabolites as well. The heterogeneity of the transcriptional system (multiple promotors and holoenzymes of the RNA polymerase) is shown to constitute an essential element of the secondary metabolism accomplishing its integration into cellular cytodifferentiation.
Optimization of some culture parameters and properties of β‐glucosidase and β‐xylosidase from Penicillium funiculosum NRRL – 13033
Authors: El‐Diwany A. I. , Hamdy A. H. A. , Farid M. A. 
Published: December 2004

AbstractPenicillium funiculosum NRRL 13033 produced β‐glucosidase and β‐xylosidase activities when grown on wheat straw. The addition of some inducers (individually or in combination) to the fermentation medium were tested for the production of both enzymes. The relation of mycelial bound enzyme to cell free enzyme was studied during incubation period of fermentation. The optimum activity of β‐glucosidase and β‐xylosidase were found to be in the pH 4.5 using phosphate‐citrate buffer at 50°C for 60 min and at 55°C for 40 min respectively. β‐Glucosidase lost about 40% of its original activity by heating to 65°C for 60 min, while, β‐xylosidase activity was found to be nearly stable with the same treatment. Both enzyme activities were greatly inhibited when 1.0% (w/v) of xylose and glucose were added to the assay mixture.