bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biochemical studies on the fermentation of cassava (manihot utilissima pohl.)
Authors: Oteng‐Gyang K. , Anuonye C. C. 
Published: December 2004

AbstractSome original observations have been made on the process of cassava fermentation to produce “foofoo”, a local nigerian diet. During the period of fermentation the pH of the fermenting liquor decreases from 6.1 to 3.4 at the end of the 6th day. The change in pH is uniform throughout the fermentation period. Decreases in dry weight of the fermenting cassava have been recorded; there is a very rapid decline during the third and fourth days of fermentation. Free reducing sugars decrease drastically within the first and second days. Total sugar concentration which is an indication of the starch content of the cassava also declines with fermentation time, and more so during the third and fourth days. Protein concentration in the liquor increases very rapidly during the first and second days of fermentation. It is believed that cassava protein is converted to microbial protein.
Organoheterotrophe Laugung resistenter Materialien
Authors: Iske U. , Bullmann M. , Glombitza F. 
Published: December 2004

AbstractLeaching processes can be classified in chemolithotrophic and organoheterotrophic mechanisms. In the case of chemolithotrophic leaching sulphide minerals, elemental sulphur, ferrous iron and a number of different reduced metals will be oxidized in a solution containing sulphuric acid of bacterial and/or chemical origin.Organoheterotrophic leaching however is connected with the accumulation of microbial metabolites such as organic acids, proteins, peptides and polysaccharides, which are capable to disintegrate ores, minerals or industrial wastes through dissolution, formation of complexes or chelates.Whereas at the present time chemolithotrophic leaching processes are in operation in industrial scale for the winning of copper, uranium and some other special metals, organoheterotrophic processes, their problems and technical applications are still under study.Therefore problems of organoheterotrophic leaching of chemical high resistant materials such as phosphorus furnace slag and zircon from the Baltic shield have been investigated with regard to possible technical applications for the winning of rare earth elements (REE) and other precious metals.Using a strain of Acetobacter methanolicus which is able to accumulate large amounts of gluconic acid on the basis of glucose or glucose containing by‐products, leaching effects up to 90% of REE could be realized in the case of phosphorus furnace slag and up to 45% in the case of zircon.
Nitrate removal from drinking water in a fluidized‐bed biological denitrification bioreactor
Authors: Holló J. , Czakó L. 
Published: December 2004

AbstractIn most industrially developed countries an increasing degree of nitrification can be observed in potential water reservoirs. High nitrate content is unacceptable by public health standards. Since contamination seems to be unavoidable, the only realistic solution is purification prior to utilization. One of the potential variations is biological denitrification with a highly intensive facility, a fluidized‐ or expanded‐bed bioreactor. Based on laboratory and pilot plant experiments, a detailed analysis is presented on the problems arising and solutions offered in the construction of a purification system meeting high quality requirements of drinking water purification. The crucial point is selection of the denitrifying microorganisms and organic matter required for denitrification, which simultaneously determines the attachment of bacteria to the support material (autoimmobilization), the intensity of nitrate removal and the character of post‐purification.
A cellulase enzymic product: Industrial processing and possible applications
Authors: Panajotov Ch. A. , Atev A. P. , Stojanov I. M. , Peev P. A. 
Published: December 2004

AbstractFrom the Engineering Biology Department of Sofia University' microbiological collection a Trichoderma species mutant strain was found to be most promissing on preparation of cellulase enzymic products. Based on solid‐phase and submerged cultures laboratory and industrial scale procedures for obtaining cellulase products were developed. Different enzyme application possibilities were investigated and the results were presented.
Gas chromatographic analysis of free fatty acids. Part 2: Determination of free fatty acids during anaerobic putrefaction
Authors: Pörschmann S. , Pörschmann J. , Liebetrau L. , Kühn I. , Pätz R. 
Published: December 2004

AbstractBy using tailor‐made capillary columns the changes of the free fatty acid spectrum during anaerobic putrefaction of piggery waste and sludge at pH 5.0–5.5 were examined. Free fatty acids with 18 to 22 carbon atoms were the main components before putrefaction. With progressive fermentation time the share of short chain acids formed from higher acids was increased.
Mikrobiologische Kohleentschwefelung
Authors: Beck D. , Heinritz H.‐J , Worbs M. 
Published: December 2004

AbstractSO2emissions arising by burning of coal represent an important ecological problem. Therefore, in international scale it is worked today in the development of techniques for solving this problem. A possibility consists in the microbial conversion of sulphur compounds of coal before its burning into compounds which not produce SO2 by burning. Sulphur is bound in inorganic and organic form in coal. The composition may strongly differ in dependence on the kind of coal and its deposit. For the bioconversion of different sulphur compounds specific microorganisms were used. The paper gives an overview about the situation and the tendencies of the research in this field and also some informations of our own research.
Zum Lichteinfluß auf Fermentorkulturen von Nigella damascena L
Authors: Schmauder H.‐P. , Döbel P. 
Published: December 2004

AbstractThe growth behaviour of a Nigella damascena cell line cultivated in airlift fermenters in darkness as well as in ligth was investigated. Considerable variations were observed with regard to the morphology of the cells, the consumption of substrate and the content of yellow pigments. The UV absorption spectra of the yellow pigments show some similarities to the spectra known for thymoquinone.
The influence of control parameters of extraction and concentration over oxidation and degradation of amino acids
Authors: Pobedimski D. G. , Pevzner I. L. , Saduikov R. A. 
Published: December 2004

AbstractThe detailed thermal decomposition characteristics of several amino acids in different fase state — dry and moist crystals (Trp, Arg HCl, Lys HCl), water solutions (Trp) are determined. It is found that thermodecomposition of Trp in water solutions is inhibited by Na2S2O3 and oxyethylidendiphosphonic acid.The method of finding optimal control parameters (temperatur of moist crystals, heating surfaces, drying agent) during amino acid drying on the bases of their thermodecomposition kinetics is given. The received results can be used for technolodical optimization of different stages of amino acid extraction and concentration processes.
Energy and reducing equivalent potential of C2‐compounds for microbial growth
Authors: Müller R. H. , Babel W. 
Published: December 2004

AbstractYeasts were chemostatically cultivated on C2‐substrates. Experimental yield figure were 0.77 g/g and 0.57 g/g on ethanol, 0.37 g/g and 0.29 g/g on acetate and ammonium and nitrate, respectively, as the nitrogen sources. Growth on hexadecane/ammonium yielded 0.94 g/g. Simultaneous utilization of formate lead to an increase of growth yield on acetate and hexadecane but not on ethanol. The experimental data were compared to theoretical figures. These results show that growth yield on ethanol/ammonium is carbon‐limited, on ethanol/nitrate is NADPH‐limited and on acetate with both nitrogen sources is energy‐limited. With hexadecane/ammonium growth yield is energy‐limited too. According to these results ethanol seems to be the only substrate from which an excess in energy can be obtained.
Conversion of lignocellulosic material to ethanol influence of raw material yield and hemicellulose utilization on sales price of ethanol
Authors: Felber J. , Schiefersteiner M. , Steinmüller H. 
Published: December 2004

AbstractIn the late 70's an Austrian Consortium consisting of the STEYRERMÜHL‐Papierfabriks‐ und Verlags AG, the Voest‐Alpine AG and the Universities of Graz was formed to develop a new process for the production of monosaccharides from renewable carbohydrate sources, in particular lignocellulosic material. After detailed examination of various hydrolytic processes it was decided to intensify work on enzymatic hydrolysis. The composition of this group brought the great advantage that it could focus not only on one problem but could also research into the total process. This included pretreatment, enzyme production, hydrolysis, by‐product utilization and energy supply.The raw materials studied most thoroughly on our program were waste paper and wheat straw, since these lignocellulosics are available in large quantities in Austria.Until now all endevour to produce ethanol out of lignocellulosic biomass on an industrial scale failed due to uneconomical production. Thus it is evident that the economy of such a process is very dependent not only on the yield of sugar, which is strongly affected by the respective pretreatment, but also on the utilization of the hemicellulose. Summarizing it can be said that the cellulose has to be degregated to a high extent and that the hemicellulose must be utilized to reach a feasible project.
Einwirkung des immobilisierten Präparates „Sirenin”︁ aus Bacillus mesentericus auf Milch als Substrat
Authors: Dobreva E. , Antonova T. , Veltscheva P. 
Published: December 2004

AbstractComparative investigations for the possibilities of milk coagulation by the action of soluble and immobilized (on DEAE‐cellulose by adsorption) bacterial enzyme preparation “syrenin” in periods from 30–120 minutes at 5°C are carried out. The milk clotting activities of both preparations are equalized after 40 minutes. The laboratory experiments for producing a bulgarian white brine cheese by the immobilized “syrenin” show a tendency to decrease the losses of substance into the whey and to increase the curdle yields in comparison with these made by soluble preparation.
Biosynthesis of cellulolytic enzymes by Aspergillus niger A.n. 33 and its selectants
Authors: Czajkowska D. , Hornecka D. , Ilnicka‐Olejniczak O. 
Published: December 2004

AbstractThe aim of the investigations was to obtain — from the parent strain Aspergillus niger A.n. 33 — selectants with an increased ability of cellulolytic enzymes biosynthesis. Own selection methods allowed to receive two selectants A.n. 33/2 and A.n. 33/20 characterized by enhanced activities of saccharifying cellulase (respectively 0.11 and 0.14 FPU/cm3), endo‐beta‐1,4‐glucanase (15.4 and 21.8 U/cm3) and cellobiase (0.6 and 1.4 IU/cm3) as compared with the parent strain (FPA — 0.09 IU, CMC — 8.2 U and CB — 0.1 IU/cm3). Moreover, the selectants differed in shape and size of conidial heads, in shape and colour of conidia, as well as in structure and shape of hyphae. Enzyme preparations obtained after ultrafiltration of liquid cultures were characterized by following activites: FPA‐4–16 IU, CMC — 900–1800 U, CB — 60–120 IU and xylanase — 250–280 IU/cm3.
Prozeßberechnung der enzymatischen Saccharosehydrolyse in Abhängigkeit von der Temperatur
Authors: Westphal G. , Vogel J. , Pusch D. 
Published: December 2004

AbstractThe calculation determining enzymatic metabolism under variable reaction conditions is possible on the basis of its reaction kinetics.In this connection a scientific and mathematical well established model is given, which allows to calculate metabolism that is catalized enzymatically. Experimental evidence for the validity of this model is given for cases both soluble and immobilized Invertase preparation are used. It is substantiated by the fact that the experimental values are in good agreement with the calculated data.
Characterization of biotechnological processes and products using high‐performance liquid chromatography (HPLC). II. Analyses of potato starch hydrolysis products
Authors: Gey M. , Becker U. 
Published: December 2004

AbstractPotato starch hydrolysis products were analyzed for glucose, maltose, higher oligomeric carbohydrates (to a degree of polymerization, dp 11) and 5‐hydroxymethylfurfural (HMF) using high‐performance liquid chromatography.For quick qualitative and quantitative analyses short glass columns [12] of high efficiency were useful.The hydrolyses were carried out by means of enzymes (e.g. α‐ and β‐amylase) or mineral acids. For the acid degradation procedures hydrochloric acid, sulfuric acid and phosphoric acid of different concentrations (0.1…2.0 N) during times ranging from 5 to 60 min at temperatures ranging from 100 to 140°C were used.Maximum glucose contents (163.4 g/l and 169.3 g/l) were found after 40 to 50 min of hydrolysis in 0.1 N hydrochloric acid heated to 120°C. These values are equivalent to 78.9% or 81.7% glucose yield referred to the initial potato starch amount, respectively. The calculated HMF concentrations were 140 and 180 mg/l.
Morphological properties of Aspergillus awamori strain overproducing glucoamylase
Authors: Witkowska‐Gwlazdowska A. , Ilnicka‐Olejniczak O. , Czajkowska D. 
Published: December 2004

AbstractIt was found that Aspergillus awamori strians suitable for glucoamylase biosynthesis in liquid (LSF) or solid medium (SSF) differ in the shape and size of conidial heads, shape and colour of conidia as well as in the structure and shape of hyphae.
Effects of temperature on microbial production IV. The influence of ethanol on the temperature‐profile curve of ethanol production
Authors: Richter K. , Becker U. 
Published: December 2004

AbstractThe shape of the temperature profile curve of ethanol production changes in the presence of ethanol. So the characteristic points of the curve are shifted to lower values at increasing ethanol concentrations. As a reason for it the potentiation of thermal deactivation effects by ethanol already at lower temperatures is assumed. Compared to it, the activation energy of ethanol for mation in the suboptimal temperature range was found to be unaffected by alcohol.
Einfluß der Kultivierungsbedingungen von Mikroorganismen auf ihre Metallsorption
Authors: Hübner K. , Iske U. 
Published: December 2004

AbstractThe silver sorption capacity of three methylotrophic bacteria and one gelatinotrophic Pseudomonas strain has been investigated in dependence of the cultivation conditions. Whereas the maximum loading capacity of the microorganisms was not appreciable influenced by the variation of the dilution rate in the range between 0.05 h−1 to 0.5 h−1, a change of the carbon source or the modification of the limitation conditions during the chemostatic cultivation process provokes a strong alteration in the sorption behaviour. The maximum silver loading values were obtained, when the microorganisms are cultivated under N‐limitation and the minimum values were measured under P‐limitation.
Modellbank Biotechnologie – Ein Softwarepaket zur Modellauswahl, Optimierung und Simulation biotechnologischer Prozesse
Authors: Goldschmidt B. , Lindner U. , Mathiszik B. , Tiller V. 
Published: December 2004

AbstractThe MODELBASE BIOTECHNOLOGY has been developed for gathering and processing data obtained from biochemical experiments. It covers the analysis of growth kinetics and production kinetics as well and may be used for calibration curve determination too. The implementation of models defined by the user is supported. Both, differential equations and their integrated forms are accepted. In addition to parameter estimation a statistical analysis can be carried on request. Two and three dimensional graphical representation facilitates the interpretation of results.Fields of application are biochemistry, biotechnology, microbiology, engineering, pharmacy, equipment design, education.
The microbiological data base of the data bank project BD1
Authors: Brüggemann L. , Sommer S. , Fiedler. E. , Karbaum K. , Albrecht C. , Hedlich R. , Nagel B. 
Published: December 2004

AbstractThe aim of the project BD1 (Biotechnology Data Bank 1) is to improve the data processing for research in biotechnology. In BD1, data of several classes of objects and methods are compiled. A data file conception consisting of object data files, method data files and feature data files was created, which can be easily extended to further classes, and which allows the combination of different classes of features to the same class of objects. There are two main approaches to use BD1: 1. making available informations on certain biotechnological objects, 2. the identification of unknown objects by means of their feature pattern.The microbiological data base and the possibilities of data base search are presented by example of lactic acid bacteria.
Möglichkeiten zur energetischen Optimierung biotechnologischer Massenproduktionsprozesse am Beispiel der Futterhefeanlagen der DDR
Authors: Püchner K. , Hemmann H.‐G. 
Published: December 2004

AbstractCalculations have been made with the aim of utilizing the waste heat released at constant rates in the large‐scale production of fooder yeast in the G.D.R. and as yet unused, for thermally concentration of fermentation products. The following results were obtained, based on left‐handded thermodynamic cycles and corresponding with the largest production plants working in the G.D.R.There is the prospect of integrated heat pump systems with direct exposure of evaporator and condenser surfaces and steam‐driven compressors supersending conventional, steam‐heated concentration systems. There is, however, a major hazard in the form of possible breakthroughs of refrigerants into the biosuspension. Processes involving what is known as vaporization cooling and operating without specific refrigeration cycles can presently not compete with conventional systems.None of the two versions can make full use of the waste heat from fermenters for thermal processing. Recovering between 20 and 30% would be an economical proposition.
Acid phosphatases purified from industrial waste mycelium of aspergillus niger used to produce citric acid
Authors: Żyła K. 
Published: December 2004

AbstractThe waste mycelium of Aspergillus niger ‘Z’ used to produce citric acid was recognized as a rich source of intracellular acid phosphatases (E.C. 3.1.3.2.). Three forms of enzyme were isolated and purified 50–150 fold according to a procedure involving ammonium sulphate fractionation, Sephadex G‐200 gel chromatography, and DEAE‐cellulose ion‐exchange chromatography.The cytoplasmic form (80% of the whole activity) was found to have molecular weight 230000, ‘MICHAELIS’ constant 2.4 mM (when measured with pNPP), optimal temperature 60°C, pH optimum 1.8–3.0 and contained 30% of carbohydrate in the molecule. This form was able to hydrolyse pNPP, beta‐glycerophosphate, inorganic pyrophosphate, glucose‐6‐phosphate, phytate, compounds and phosvitin, but did not hydrolyse beta‐casein nor leeithin.One of two forms connected with the cell walls shown similar properties, whereas the other had molecular weight of 9500, ‘MICHAELIS’ constant 1.4 mM, pH optimum 5.0 and was much less thermostable.
Production of L‐tryptophan
Authors: Plachý J. , Ulbert S. 
Published: December 2004

AbstractA precursor method of L‐tryptophan production using Corynebacterium glutamicum CCM 3358 resistant ot indole was developed. When the dissolved oxygen level was maintained optimal by a periodic pH adjustment and different doses of indole were added the mutant produced 10.5 g/l tryptophan after a 55‐h cultivation.
Production of l‐phenylalanine by double auxotrophic mutants of arthrobacter globiformis: Optimization of c and n‐source
Authors: Maiti T. K. , Chatterjee S. P. 
Published: December 2004

AbstractA number of tryptophan plus tyrosine double auxotrophic mutants isolated by NTG treatment of a glutamic acid prodcing strain of A. globiformis were found to excrete phenylalanine alone in glucose, ammonium chloride, mineral salt medium. Among 24 different carbon sources tested glucose was found to be the best and optimum for ‐phenylalanine production was at 350 mM level. Among 14 different inorganic and organic nitrogen sources tested ammonium chloride was the best and was optimal at 60 mM level for phenylalanine production. On the optimum level of C and N sources a yield of 1.5 g/l phenylalanine was achieved.
A Purified α‐galactosidase from aspergillus niger with enhanced kinetic characteristics
Authors: Agnantiari G. , Christakopoulos P. , Kekos D. , Macris B. J. 
Published: December 2004

AbstractExtracellular α‐galactosidase from Aspergillus niger was purified 128‐fold over the crude extract by gel filtration, ion exchange chromatography and chromatofocusing. Certain substrates and end products affected enzyme activity. Among the former p‐nitrophenyl‐α‐galactopyranoside (PNPG) inhibited the enzyme at 1.4 mM while melibiose did not inhibit α‐galactosidase at concentrations up to 50 mM. Enzymic end products such as glucose did not inhibit the enzyme at concentrations up to 100 mM while galactose exhibited a competitive inhibition with a Ki = 1.29 mM. The kinetic characteristics of the enzyme compared favourably to other microbial α‐galactosidases and make it suitable for food process applications.
Affinity chromatography of 1,4‐β‐glucosidase from trichoderma reesei QM 9414
Authors: Rogalski J. , Wojtas‐Wasilewska M. , Leonowicz A. 
Published: December 2004

AbstractThe separation and purification method of extracellular cellobiase and aryl‐β‐glucosidase from Trichoderma reesei by means of affinity chromatography on controlled porosity glass activated by ι‐aminopropyltriethoxysilane and oxiranes are described.
Contributions to the biotechnological production of sweeteners from stevia rebaudiana bertoni. II. Induction of stevioside accumulation in cell cultures by variation of the nutrient medium and the analysis of small amounts of stevioside
Authors: Striedner J. , Gutjahr E. , Czygan F.‐C , Braunegg G. 
Published: December 2004

AbstractCell cultures of Stevia rebaudiana in general do not contain stevioside when grown on their basal nutrient medium. No stable and prolonged stevioside accumulation was achieved by varying the medium components. However, in some cases a transient state was observed where more stevioside was synthesized than catabolized. The dynamic behaviour of product synthesis which led to accumulation of stevioside during only a short period was demonstrated. For accurate determination of very small amounts of stevioside, a combined TLC‐HPLC method was used [1].
Contributions to the biotechnolgical production of sweeteners from stevia rebaudiana bertoni. III. Accumulation of secondary metabolites by means of a precursor and by elicitation of cell cultures
Authors: Striedner J. , Geissler S. , Czygan F.‐C , Braunegg G. 
Published: December 2004

AbstractGibberellin A3 fed to cell suspension cultures of Stevia rebaudiana showed a fast conversion to stevioside. The product was detected within one day after gibberellin addition and achieved its maximum concentration after one week. However, using special production media (without precursor or elicitor), stevioside was produced only two to seven weeks after inoculation [1]. Elicitation of suspension cultures was performed with Stevia specific and non‐specific fungi and with yeast extract. Although production of some secondary metabolites was induced, stevioside was not synthesized.