bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chitin and its derivative as supports for immobilization of enzymes
Authors: Krajewska B. 
Published: December 2004

AbstractThe ideal enzyme support should show high affinity to proteins, availability of reactive groups for direct reactions with proteins or for chemical modifications, easiness of preparing in different physical forms, nontoxicity and physiological compatability if required (food industry, biomedicine), as well as low cost. Chitin and its derivatives fullfil most of these requirements. The paper reviews enzymes immobilized on chitin and its derivatives along with techniques applied for their immobilization.
Synergism of isoenzymes of cellobiohydrolase I and II of trichoderma reesei in hydrolysis of amorphous cellulose
Authors: Heithz H.‐J. , Witte K. , Wartenberg A. 
Published: December 2004

AbstractDecompositions of amorphous cellulose induced by cellulases of Trichoderma reesei were evaluated from gradients at zero time of exponential functions which were fitted to nephelometrically measured values of turbidty of incubated solutions of cellulose [turbidity = A × exp (B × t)+ C [A, B, C = constants, t = time]]. Synergistic enhancements of decomposition of amorphous cellulose resulted in the range of 300 p.c. whenever of the two isoenzymes of cellobiohydrolase I of Trichoderma reesei (CBH I, being an exo‐glucanase) one was incubated together with one of the isoenzymes of CBH II (being really an endo‐glucanase). Accessibility of amorphous cellulose to enzymatic decomposition being calculated from the fitted function by the term (A/(A + C)) × 100 [p.c.] resulted for the CBH I isoenzymes and for the CBH II/1 in the range of 27 to 38 p.c. of the total substrate. Incubations of CBH II/1 in with CBH I/1 and CBH I/2 were followed by increases of accessibility to 85 and 87 p.c., respectively. CBH II/2 by itself caused a substrate accessibility in the range of 80 p.c., which increased to 96 p.c. when it was incubated together with CBH I/1 or CBH I/2. Amorphous cellulose dispersing activity (ACD activity) being evaluated from the fitted function by the term (A + C)/(Ac + Cc) × 100 [p.c.] (Ac + Cc × control turbidity at zero time) was not increased when a CBH I isoenzyme was incubated together with a CBH II isoenzyme. EG I, a convetional endo‐glucanase from Tr. reesei proved not to act synergistically in any case when incubated together with one of the CBH isoenzymes. On the contrary, EG I turned out to act antagonistically to CBH II/1 and CBH II/2. Results can be interpreted as an exo‐endo‐synergism taking place between C1‐specific exo‐ and endo‐glucanases.
Isolation of biosurfactant‐producing bacteria, product characterization, and evaluation
Authors: Abu‐Ruwaida A. S. , Banat I. M. , Haditirto S. , Salem A. , Kadri M. 
Published: December 2004

AbstractA gram‐positive, nonfermentative, rod‐shaped bacterium designated ST‐5, identified as Rhodococcus, was isolated from Kuwait soil. Grown on hydrocarbon, such as kerosene and n‐paraffin, the bacterium produced surface‐active compounds (biosurfactants). Measurements of surface tension, critical micelle dilution and emulsifying activity indicated that the biosurfactant is produced as a primary metabolite. The ST‐5 culture surface‐active component is mainly glycolipid in nature. Whole‐culture broth dropped surface tension to values below 27 mN/m and was stable during exposure to high salinity (10% NaCl), elevated temperatures (120°C for 15 min) and a wide range of pH values. The culture broth was effective in recovering up to 86% of the residual oil from oil‐saturated sand packs, indicating potential value in enhanced oil‐recovery processes.
Growth efficiency of thielavia terrestris mycelial structures
Authors: Gromosova E. N. , Fomina M. A. , Podgorsky V. S. , Leite M. P. , Zeltina M. O. , Shvinka Y. E. 
Published: December 2004

AbstractThe growth energetic efficiency (η) of two mycelial forms of Thielavia terrestris (pellets and diffused form) was studied by different methods. η Values determined by the pulse method are similar for the two forms, but the values determined by C balance for pellets were lower than those for diffused mycelium. These balance data prove that pellets yield more extracellular products than the diffused mycelium form, which is also confirmed by experimental data for different amounts of carbon in the culture fluid.Growth efficiency can be determined by various methods based on the principles of mass and energy balance. The estimates most frequently used are the biomass and substrate balances. However, growth efficiency determination according to oxygen balance (particularly by the pulse method) is simpler and more accurate; as it makes possible the immediate fixation of changes in the physiological condition of microorganisms and the determination of complex substrate utilization efficiency [1]. Earlier the possible use of this method for evaluating the growth efficiency of heterotrophic bacteria [2], hyphalic and yeast forms of microscopic fungi [3] was shown. The aim of the present study is the comparative investigation of the growth efficiency of two mycelial structures (hyphalic and pellets) by different methods as well as by pulse additions.
Nitrogen – a guide element in the bioconversion of lignocellulosics
Authors: Weichert D. , Schröouter H. 
Published: December 2004

AbstractSeveral balanced experiments of protein enrichment have shown that if ammonia is the sole N source in the bioconversion of lignocellulosics, significant data on the process can either be received from the N consumption determined, or from fixed organic nitrogen.Nitrogen can be a guide element for such data as cell biomass, utilized substrate, degree of bioconversion, specific substrate consumption coefficient, crude protein and crude protein yield, which are all necessary for the classification of fungi and substrates as well as for process characterization and optimization.
Kinetic analysis and modelling of streptokinase fermentation
Authors: Stuebner K. , Boschke E. , Wolf K.‐H. , Langer J. 
Published: December 2004

AbstractThe kinetics based on the MONOD conception of anaerobic, discontinuous, isothermal, isobaric fermentation producing a special protein in secondary metabolism is studied.The kinetic analysis results in a growth limitation by the primary product which shows a sigmoidal behaviour, a lineary correlation between the specific substrate degradation and the specific rate of formation lactic acid and a lineary correlation in a good approximation between the formation of proteins and substrate degradation.In this study a process model with coupled differential equations is provided. Kinetic and stoichiometric coefficients are determined.
Formation of ethanol and higher alcohols by immobilized zymomonas mobilis in continuous culture
Authors: Oaxaca V. A. , Jones L. P. 
Published: December 2004

AbstractCells of Zymomonas mobilis ATCC 10988 were immobilized in 1.5% calcium alginate and packed in a column bioreactor for a series of fermentations utilizing 10.0% glucose media with the addition of one of the following amino acids or keto acids: L‐leucine, L‐isoleucine, L‐valine, α‐ketoisocaproic acid, α‐ketobutyric acid, or α‐ketoisovaleric acid. This was done in order to study the rates of production of higher alcohols during ethanolic fermentations at varying dilution rates while under the influence of amino acids or keto acids.Results indicate that the EHRLICH mechanism is operative in Zymomonas sp. α‐Ketobutyrate enhanced the production of n‐propanol and act‐amyl alcohol. α‐Ketoisocaproic acid stimulated the production of isoamyl alcohol. α‐Ketoisovaleric acid increased the levels of isobutanol. The amino acids also gave rise to their corresponding alcohols but to a far lesser degree than did the keto acids. During high glucose utilization, ethanol yields ranged from 87% to 94% of theoretical with productivity ranging from 60.08 g/l/h in one fermentation (at a dilution rate of 1.35 h−1) to 70.42 g/l/h in another (at a dilution rate of 1.58 h−1). At dilution rates of 1.58 h−1, higher alcohol productivity rose to as high as 4,313 mg/l/h in the presence of α‐ketoisocaproic acid, 1,734.49 mg/l/h using α‐ketoisovaleric acid, and 1,618.05 mg/l/h in α‐ketobutyric acid. The concomitant production of ethanol and higher alcohols in all of the fermentations indicates that glucose is required for the production of the higher alcohols from their corresponding amino acids or keto acids.
Laboratory glass fermenter on the basis of the airlift principle
Authors: Schiemenz E. , Wendlandt K.‐D. , Mirschel G. , Simon D. 
Published: December 2004

AbstractA 1.5‐1 minifermenter consisting of RASOTHERM glass on the basis of the airlift principle was constructed and tested in the Institute of Biotechnology.The development of this fermenter bridged the gap between shake flasks and lab‐scale fermenters and provided a possibility for the continuous cultivation of extremely halophilic bacteria. It was demonstrated that the fermenter can be used for cultivating bacteria that are sensitive to shear stress. It can also be recommended for purposes of cultivation of plant and animal cells because of this advantage and the possibility of this fermenter to be sterilized.
Biotransformations of industrial use
Authors: Kieslich K. 
Published: December 2004

AbstractBiotransformations represent a useful tool for the production of various chemical compounds because of their main advantages: attack of non‐activated positions, regio, stereo and enantio‐selectivity, and the mild reaction conditions.Organic chemistry can use these advantages in various enzymatic type reactions.One of the most interesting and promising groups of these biotransformations are the various oxidative reactions.The following article intends to give a short insight in the present state of this part of the broad field of biotransformations.Examples of technically interesting processes, preferably results of newer developments, should illustrate

the variety of enzymatical oxidative reactions used.
the various structures of educts for aimed oxidative modifications and.
the application in the pharmaceutical, food and chemical industries.
Isolation of auxotrophic mutants from acetobacter methanolicus MB 58
Authors: Föllner C. , Babel W. 
Published: December 2004

AbstractThe lysine content of the biomass of the acidophilic facultatively methylotrophic bacterium Acetobacter methanolicus MB 58 was increased by genetic manipulations.A homoserine auxotroph, MB 58.196, and a threonine auxotroph, MB 58.195, were obtained from Acetobacter methanolicus MB 58 by N‐methyl‐N′‐nitro‐N‐nitrosoguanidine treatment.Investigations of enzyme activities revealed that the homoserine auxotroph lacks homoserine dehydrogenase activity, and the threonine auxotroph lacks homoserine kinase activity.Concerning the lysine‐producing ability, only the homoserine auxotrophic mutant accumulates lysine in the intracellular pool. The intracellular lysine content of this mutant was increased 40‐fold.An excretion of amino acids into the medium was not detected. A homoserine resistant mutant, MB 58.196.10, isolated from MB 58.196 by UV‐irradiation, was able to excrete lysine. About 95% of free lysine were found in the culture medium. Altogether, the free lysine concentration was increased 800‐fold in comparison to the wild‐type strain.By these genetic manipulations the total lysine concentration of MB 58.196 was increased to 2.7% and of MB 58.196.10 to 56% in comparison to the wild‐type strain.
High performance bacterial fermentation process with two gaseous substrates
Authors: Pöhland H.‐D. , Hühn H. J. , Klarmann H. , Prause M. , Soyez K. 
Published: December 2004

AbstractTwo methane utilizing bacteria strains, GB 21 and WSB 874, were cultivated with methane as sole carbon and energy source in a submerged continuous fermentation process. The aim of the investigations was to reach high biomass concentrations (>25 g BDM ·kg−1 medium) and high productivities (>3 g BDM · kg−1 · h−1). A precondition for the high‐performance fermentation process was to ensure a transfer rate of methane and oxygen in quantities required by the microorganisms. For this purposes a high performance stirred pressure fermenter was used. The fermentation process is characterized by the transfer of two gaseous substrates. In order to develop a technical process it was necessary to investigate both the correlations between the two gases and the productivity of the fermentation process and the influence of system pressure on the microorganisms.Within a pressure range of up to 0.7 MPa a biomass concentration of up to 50 g BDM · kg−1 medium and a productivity of up to 9 g BDM · kg−1 · h−1 was reached in a continuously running fermentation process under nonsterile conditions. Under these fermentation conditions the microbial population consisted of a dominating main culture GB 21 or WSB 874, respectively, and an accompanying flora (type II). The microbial population was very stable in its composition during the fermentation process running continuously for weeks and months.
“Ecological biotechnology” – the new dimension in technology
Authors: Moser A. 
Published: December 2004

AbstractEcological restructuring of all areas is the most essential action needed for the future of our cultures on earth.This paper intends to clarify how human technology activities can be embedded in the cycles of the biosphere.A new quality of life will be maintainable by this concept of ecologically sustainable technology.The background of this innovation is explained in more detail and the fundamentals are eluciatated comprehensively. A series of principles of general validity are derived from the study of ecosystems in biosphere, which are to be transferred to technologies. This will result in the new technology paradigm of “ecologic process engineering” which is part of a new paradigm in sciences.
Hollow fibre modules as membrane reactor in biocatalysis
Authors: Luther H. , Hirsch S. , Schuster E. , Weber E. 
Published: December 2004

AbstractAs shown in the case of the enzymatic cleavage of Penicillin G by Penicillin acylase hollow fibre modules of the type MLW (molecular separation value of 10,000 Dalton) produced for blood dialysis are also suitable as membrane reactor.The enzymes physically bound in the hollow fibre allow a reproducible reaction rate and are characterized by an acceptable stability.The studies indicate an operating stability which makes possible low production costs of amino penicillin acid.
Molecular cloning of the gene, expression in E. coli and purification of the thermus aquaticus DNA polymerase I
Authors: Lleonart R. , Campos M. , Suáarez A. , Vaźquez R. , de la Fuente J. , Herrera L. 
Published: December 2004

AbstractThe Thermus aquaticus DNA Polymerase I gene was isolated by using standard recombinant DNA techniques and cloned into an E. coli vector in front of the lac promoter. E. coli cultures produced thermostable polymerase when induced with the analog IPTG. A purification procedure is shown which renders an enzymatic preparation suitable for PCR reactions.
Effect of different nitrogen and carbon sources on the proteolytic activity
Authors: Ibañez A. M. , Altuna B. , Díaz de Villegas M. E. 
Published: December 2004

AbstractTwo‐three fold increases in the levels of proteolytic activities in one strain of Bacillus licheniformis (R1‐8) were obtained when changes in the nature of the nitrogen source (food and fodder yeast instead of soybean meal) and in the amount of invert sugars in the culture medium were performed.
Nutritional conditions for the germination of streptomyces galbus 5ME‐13 spores
Authors: Sengupta S. , Paul A. K. 
Published: December 2004

AbstractThe nutritional conditions for the germination of spores of Streptomyces galbus 5ME‐13 were determined under laboratory conditions. The germination of the spores was intiated by the emergence of 1–2 germ tubes after the second hour of incubation and attained its maximum at the sixth hour. This was accompanied by a steady rise in the optical density of the germinating spore suspension. A malt‐extract yeast‐extract medium was found to be the best medium for the germination of the spores.Glycerol as the sole source of carbon was the best supporter for spore germination while, as N source, L‐alanine was preferred. The optimum pH and temperature for spore germination were 7.2 and 30°C, respectively.
Cellulase secretion by immobilized protoplasts of Trichoderma reesei
Authors: Marinova D. N. , Atev A. P. 
Published: December 2004

AbstractProtoplasts from Trichoderma reesei were immobilized in alginate and induced to produce cellulase (endoglucanase and β‐glucosidase) enzymes. The specific activities of the synthesized enzymes were higher in immobilized protoplasts than in both free and immobilized mycelia.Immobilized protoplasts show an enhanced rate of exocellular β‐glucosidase production compared to intact mycelia due to the lack of cell wall. The ratio of the exocellular/intracellular β‐glucosidase was 5.9 for immobilized protoplasts and 0.32 for free mycelia.
Transformation of D‐xylose by sporobolomyces lactosus
Authors: Proksa B. , Sláviková E. , Uhrínová S. 
Published: December 2004

AbstractThe new yeast species, Sporobolomyces lactosus, transformed D‐xylose into a mixture of disaccharides. Hydrolysis of this mixture yielded D‐glucose only. The main component of disaccharide mixture was α,α‐trehalose.
Some biological characteristics of the casing soil and their effect during Agaricus bisporus fructification
Authors: Cochet N. , Gillman A. , Lebeault J.‐M. 
Published: December 2004

AbstractThe intent of this work was to study the biological and biochemical aspects of the casing soil role on every stage of the A. bisporus fructification. We reported the development of mycelial thick threads of A. bisporus in the casing soil.Moreover, we pointed out the protective role of the calcium salts crystals surrounding the hyphae during the incubation stage. On the electron‐micrographies, the mycelial aggregates were surrounded by bacteria, and this bacterial growth seemed to be related to the calcium salts crystals disappearance.The positive influence of A. bisporus upon bacterial growth, and vice versal, was confirmed with PETRI dish cultures.
Studies on root nodules of leguminous plants bioproduction of indole acetic acid by a Rhizobium sp. from a twiner Clitoria ternatea L.
Authors: Roy M. , Basu P. S. 
Published: December 2004

AbstractThe Rhizobium sp. isolated from the root nodules of Clitoria ternatea L., a leguminous twiner, produced a high amount of IAA (16.4 μg/ml) from tryptophan in an unsupplemented basal medium. The production of IAA started simultaneously with the growth and had no different growth and production phase. The growth and production were parallel and increased up to 45–50 h. The IAA production by the Rhizobium sp. was increased by 520% when the medium was supplemented with fructose (1.5%), MnSO4 (1.0 μg/ml), riboflavin (0.10 μg/ml) and Triton X‐100 (0.01%). The possible role of the rhizobial production of IAA on the rhizobia‐legume symbiosis is discussed.
Perspectives of phototrophic microorganisms in environment protection and ecology
Authors: Pulz O. , Kretschmer P. 
Published: December 2004

AbstractThe ecophysiological properties – light effectuated neosynthesis of biomass from inorganics – make microalgae become interesting organisms of preventive and sanitating environmental protection with regard to the inorganic impact. They are filling an underestimated gap.Medium‐term solutions of the heavy metal accumulation in the tertiary sewage disposal, the trophy sanitation of surface and ground waters and of algal induced recultivation of waste‐land seem to be attainable.The investigation of the role of microalgae in world‐wide material cycles will be of long‐term importance to biotechnology and global ecology.
Methods of artificial intellect in controlling biotechnological processes (Part 1)
Authors: Kristapsons M. , Sarkisyants L. 
Published: December 2004

AbstractPresently, an urgent problem is the application of artificial intellect (AI) methods as a complex way of controlling and optimizing technological processes. The paper presents major principles of a bystage application of AI in biotechnology as knowledge extraction from data obtained by decomposing the sign space to clusters.
Purification and enzymatic properties of α‐galactosidase from Penicillium janthinellum
Authors: Elshafei A. M. , Foda M. S. , Aboul‐Enein A. , Afify A. S. , Ali N. H. 
Published: December 2004

Abstractα‐Galactosidase (E.C.3.2.1.22) from Penicillium janthinellum was purified by precipitation and fractionation with ammonium sulphate, cold acetone or ethanol, calcium phosphate gel, and column chromatographies on Sephadex G‐100 and G‐200. The enzyme was purified about 110.39‐fold when Sephadex G‐100 was used. α‐Galactosidase exhibited the optimum pH and temperature at 4.5 and 60°C, respectively. The optimum enzyme stability was obtained at pH 3.5 for 24 h (at room temperature). The enzyme was found to be thermostable below 65°C up to 40 minutes and was gradually inactivated by increasing the temperature above this degree. The MICHAELIS constant was 0.55 mM for p‐nitrophenyl‐α‐D‐galactoside. The α‐galactosidase activity was strongly inhibited by Hg++ and slightly activated by Mn++. The results show the possibility of producing a thermostable enzyme from a low‐priced agricultural product, for instance, lupine.
Production of propionic acid by microbiological way. Part 2. Effect of the pH value on cell growth and acid production
Authors: Obaya M. C. , Ramos J. , Villa P. , Valdés E. , Eng F. 
Published: December 2004

AbstractThe batch propionic acid fermentation of sugar cane molasses by Propionibacterium acidi propionici PP‐1 was studied at various pH values ranging from 5 to 7. The optimum pH range for cell growth was between 6 and 7, whereas the specific growth rate decreased with the pH in the acidic range down to 0.197 h−1 at pH 5.The propionic acid yield increased with decreasing pH; it changed from 22% (wt/wt) at pH 7 to 38% at pH 5. It has been obvious that this process is inhibited by the products of the fermentation and more severely in the acidic range where the acids are in an unionized state.A generalized equation of the non‐competetive inhibition was adjusted for each pH value, and kinetic inhibition constants were estimated.
The influence of MAILLARD's reaction in sugar cane molasses on the kinetic fermentation parameters of Candida utilis NRRL Y‐660
Authors: Otero M. A. , Reyes A. , González J. , Peña M. A. 
Published: December 2004

AbstractGrowth inhibition of Candida utilis NRRL Y‐660 took place in molasses stored at 60°C for 120 days. The specific growth rate (μmax) was reduced from 0.42 h−1 to 0.200 h−1 as a result of a lack of affinity from the microorganism to the substrate and the increasing maintenance necessities. The Ks values arose from 1.40 mg/ml to 4.28 mg/ml within the whole experiment. At the same time, the maintenance coefficient (m) increased from 0.250 to 3.80 mg/ml. In a continuous culture the “wash‐out” conditions were reached at dilution rate values (D) close to 0.40 h−1. The process productivity decreased up to 15% from its original value in fresh molasses.
L‐Methionine production by double auxotrophic mutants of a ethionine resistant strain of Brevibacterium heali
Authors: Mondal S. , Das Y. B. , Chatterjee S. P. 
Published: December 2004

AbstractA number of lysine plus threonine double auxotrophs have been isolated from a ethionine resistant methionine producing strain of Brevibacterium heali previously isolated from soil by mutagenesis with N‐methyl N′‐nitro‐N‐nitrosoguanidine in two steps. This strain excreted L‐methionine in sufficient amounts. For the three potent mutants tested, the medium of ALFOLDI was judged to be the best. Biotin and ammonium nitrate were found to be optimal at 5 μg/l and at a 40 mM level, respectively. With such an optimal dose, the strain BhLT 27 yielded 25.5 g/l methionine in a flask culture containing methionine‐analogue ethionine at a minimal inhibitory concentration.