bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phlebia radiata laccase forms induced by veratric acid and xylidine in relation to lignin peroxidase and manganese‐dependent peroxidase
Authors: Rogalski J. , Leonowicz A. 
Published: December 2004

AbstractWhite‐rot basidiomycete Phlebia radiata grown in the nitrogen‐poor liquid medium was tested for the inducing effect of 2,5‐xylidine and veratric acid on laccase production and properties of its preparations. Also lignin peroxidase and manganese‐dependent peroxidase were assayed under the same conditions. The maximum of laccase activity for veratric acid as a stimulator was done much earlier than that of xylidine. It was very sharp and disappeared quickly. At that time only weak lignin peroxidase and manganese‐dependent peroxidase activities were noticed. The maximum of laccase induced by xylidine was observed much later and kept longer. Both laccase preparations showed the same properties. For biotechnological reasons, the production of laccase induced by the nontoxic veratric acid is much more economic and better acceptable than that induced by xylidine.
The growth conditions of cephalosporium eichhorniae for the conversion of starch substrates to protein
Authors: Nguyen Van Ba B. , Bednarski W. , Kowalewska‐Piontas J. , Tomasik J. 
Published: December 2004

AbstractThe protein synthesis by Cephalosporium eichhorniae on substrates containing starch was evaluated at different pH, moisture content, ammonium sulphate and potassium dihydrogen phosphate supplementation. The optimum pH level was about 4.2 and the moisture content 65%. The optimum level of supplementation of medium containing sweet potato substrate with (NH4)2SO4 was smaller than that for cassava substrate (5.2 g/l < 6.7 g/l in submerged culture, and 4.0% < 5.2% in solid state fermentation). The total crude protein yields were about 7.6 g/l for submerged cultures and 12% DM for solid state fermentations.
Permeabilization of covalently immobilized saccharomyces cerevisiae
Authors: Jirků V. 
Published: December 2004

AbstractThe effect of solvents, ionic detergent, and drying on the passive membrane permeability of free and immobilized yeast cells was studied. The immobilization by covalent linkage was shown to affect the membrane composition as well as the individual susceptibility of cells to a permeabilization procedure.
Immobilization of β‐glucosidase from different sources on nylon tube
Authors: Woodward J. R. , Radford A. , Rodriguez L. , Aguado J. , Romero M. D. 
Published: December 2004

AbstractCellulase from four different fungi and β‐glucosidase from almonds were immobilized on the inner surface of nylon tubing. The highest values of β‐glucosidase activity retention on the support were obtained when P. funiculosum and N. crassa were used as the enzyme source. A comparative study of the thermal stability referring to β‐glucosidase activity was developed using free and immobilized enzymes. The most stable β‐glucosidases (from P. funiculosum and A. niger) did not show an appreciable change in its thermal stability after immobilization. An important increase in thermal stability was observed when less stable β‐glucosidases (from T. reesei, N. crassa and almonds) were immobilized.
Flow‐cytometric investigation of sterol content and profliferation activity of yeast
Authors: Müller S. , Lösche A. , Bley Th. 
Published: December 2004

AbstractTo understand and control the dynamics of microbial growth and metabolism, a theoretical background based on segregated models is necessary, and therefore flow cytometry is the suitable measuring method.It is shown that additional information to the usual mean‐value information, and to the well‐known cytometric methods for determining DNA content and size/shape measurement by scattered light, like the distribution of membrane sterol content of baker's yeast, leads to a more detailed knowledge of growth dynamics.We have found, that a low content of membrane sterols is a characteristic of cells with suppressed proliferation activity, but necessary for high fermentation activity. Also, a high content of membrane sterols seems to enhance the viability and survival capability of harvested and dryed baker's yeast cells. Therefore, we recommend harvesting cells at a point of medium content of membrane sterols.
Biotransformation of furfural by yeast cells covalently bound to cellulose granules
Authors: Ivanova N. , Yotova L. 
Published: December 2004

AbstractA covalent binding to cellulose granules of two yeast strains Candida tropicalis and Trichosporon cutaneum was achieved. The maximum activity for destroying furfural by the immobilized cells was obtained when the procedure conditions were: reaction medium at pH 5.0, 20°C and cell suspension concentration of 80 mg/ml. The continuous furfural transformation was studied using a growth medium in a fermenter with immobilized Trichosporon cutaneum in which a 84% bioconversion was achieved. The reduced values of furfural remained constant even after 10‐fold transformation.
The influence of pressure on the growth of methanotrophic bacteria
Authors: Wendlandt K.‐D , Jechorek M. , Brühl E. 
Published: December 2004

AbstractThe growth rate and the maximum cell concentration of methanotrophic bacteria are limited by the transfer of methane and oxygen to the culture fluid. The operation under moderate pressure results in an increase in driving force for the mass transfer of both nutrients and, therefore, in a large increase in the attainable biomass concentration.Our laboratory pressure fermenter with a volume of 12 litres operates under a system pressure of up to 0.5 MPa. In this reactor a maximum productivity of 6 g biomass/lh is achieved. However, operating under moderate system pressure and exhaust gas recycling has also disadvantages because the concentrations of the gas phase components may inhibit the growth process.From the results of the laboratory fermenter we have developed kinetic models of the influence of dissolved oxygen and carbon dioxide on the specific growth rate of the methanotrophic strain GB 25. These models are the basis for processing under increased system pressure and exhaust gas recycling.
Nutrition and broth alterations in the lactic acid fermentation
Authors: Heriban V. , Sitkey V. , Šturdík E. , Matuš P. 
Published: December 2004

AbstractIn order to optimize the thermophilic lactic acid fermentation on saccharose as the sole carbon source and improve the effectiveness of the process, alternative nitrogen sources were tested and a minimal broth composition was found. Of the alternative nitrogen sources, whey protein hydrolyzate (WPH) was the best; the broth composition was reduced from seven down to three items. Application of ammonium as a neutralizing agent instead of sodium hydroxide brought an important positive change.
Oxygen transfer efficiency in the biosynthesis of antibiotics in bioreactors with a modified RUSHTON turbine agitator
Authors: Roman R. V. , Gavrilescu M. 
Published: December 2004

AbstractIn this work, the oxygen mass transfer efficiency and power consumption in a non‐biological system and an antibiotic biosynthesis process, using a modified RUSHTON turbine agitator, were investigated. It was demonstrated that a simple modification of the blades through the increase of the blade height, simultaneously with the discontinuation of the blade surface, could improve the oxygen transfer efficiency by about 30%.Experiments performed in stirred tank bioreactors with an overall volume of 20 m3, equipped with the modified RUSHTON turbine agitator, showed that the power consumption diminished by a factor of 1.18 to 1.6 during the fermentation processes of Streptomyces erithreus, Streptomyces griseus, Streptomyces noursei, and Nocardia mediaterranei, compared to the witness bioreactor.The use of the modified RUSHTON turbine for the antibiotic biosynthesis process may contribute to the decrease of the overall costs and the obtainment of better productivity, allowing an intensive utilization of power inputs for aeration and agitation.
Optimization of the conditions of the fermentation of beet molasses to lactic acid by Lactobacillus delbrueckii
Authors: Monteagudo J. M. , Rodríguez L. , Rincón J. , Fuertes J. 
Published: December 2004

AbstractOptimization studies were carried out for the production of L‐lactic acid from the fermentation of beet molasses by Lactobacillus delbrueckii. A Central Composite Design was used to determine the optimum values of the process variables (temperature, pH, inoculum concentration, and initial sucrose concentration) for obtaining the maximum yield and the maximum volumetric productivity of lactic acid. Among the variables selected for study, it was found that all of them apart from the temperature significantly affected the responses (yield and volumetric productivity of lactic acid). The Central Composite Design also permitted formulating two second‐order polynomial empirical models relating to the responses and the significant variables. From these models it was possible to determine the value of the variables giving the maximum yield of lactic acid production (87.8%) and the maximum volumetric rate of lactic acid biosynthesis (2.7 g/l · h). Finally, the dependence of the lactic acid yield and productivity on the model variables was investigated. All conclusions are restricted to the experimental range studied.
The variability of the hypericin content in the regenerants of Hypericum perforatum
Authors: Čellárová E. , Kimáková K. , Halušková J. , Daxnerová Z. 
Published: December 2004

AbstractThe hypericin content of in vitro regenerated plants of Hypericum perforatum L. was determined by spectrophotometry. A significant variability of some of the morphological characters, of the biomass production and the hypericin formation was found within the somaclones of the same genetic origin and among the regerants of different genotypes. The concentration of BAP which promoted the shoot differentiation did not affect the hypericin content and the gland density. New information on the ultrastructure of hypericin‐containing multicellular glands is presented here.
Biotechnological methods for the up‐grading and modification of animal waste fats
Authors: Bednarski W. , Adamczak M. , Kowalewska‐Piontas J. , Zadernowski R. 
Published: December 2004

AbstractThe possibility of producing monoacyloglycerols (MAGs) from poultry fat or beef tallow using selected microorganisms or enzymatic glycerolysis was established. The highest content of MAGs (16.21–17.63% w/w) in the lipids was obtained after the cultivation of Candida lipolytica on a medium with poultry fat. The concentration of MAGs in the lipids which remained in the medium was influenced by the microorganisms strains and their cultivation conditions. The yield of MAGs obtained by the enzymatic glycerolysis of poultry fat or beef tallow ranged from 3.52% to 55.10% w/w, respectively.
Formation of a micronuclei‐like structure induced by colchicine treatment in Saccharomyces cerevisiae
Authors: Toyama H. , Toyama N. 
Published: December 2004

AbstractMinute nuclei named “smaller nuclei” were generated when the cells of Saccharomyces cerevisiae were treated with colchicine. The formation of “smaller nuclei” seemed to be related to nuclear division because those nuclei were only produced under conditions suitable for nuclear division. The fact that the average DNA content of “smaller nuclei” was almost one tenth of that of the isolated normal diploid nuclei showed that the “smaller nuclei” are not condensed nuclei but aneuploid nuclei like micronuclei in animal cells. It appeared therefore likely that a micronuclei‐like structure could be produced by colchicine treatment in S. cerevisiae.
Production of thiaminase I for analytical purposes
Authors: Ruml T. , Silhánková L. 
Published: December 2004

AbstractA simple medium enhancing the production of thiaminase I (EC 2.5.1.2) by Bacillus thiaminolyticus was developed. Ca2+ stimulated the enzyme production. The activity of extracellular thiaminase I ranged between 1.29 and 1.33 U/ml medium.
The purification and immobilization of Penicillium notatum β‐galactosidase
Authors: Rogalski J. , Łobarzewski J. 
Published: December 2004

AbstractPenicillium notatum No. 1 as a producer of β‐galactosidase was cultivated in a 5–1 fermenter. Various methods of protein isolation and concentration from the culture fluid were optimized. Then the conditions of β‐galactosidase purification using an affinity chromatographic technique were established. The purified enzyme was immobilized on a controlled porous glass (CPG). The optimum temperature and pH values of the native and immobilized forms of β‐galactosidase were determined as 50°C and 30–50°C as well as pH 3 and pH 3–5, respectively.
Cultivation of a filamentous mould in an airlift bioreactor
Authors: Gavrilescu M. , Roman R.‐V. 
Published: December 2004

AbstractCephalosporin C biosynthesis was investigated in a pilot‐plant external‐loop airlift bioreactor for evaluating the capacity of this bioreactor to surpass the problems which arise from the morphology of the mould and the rheology of the broth.Some of the results were compared with those obtained in a stirred tank bioreactor.The dilution and the use of static mixers was necessary to overcome the effects of the high viscosities. The oxygen transfer rate represented 84% of that in the stirred bioreactor, but the efficiency of the power utilization was higher.The specific productivity of Cephalosporin C is comparable to that obtained in the stirred tank bioreactor, but the average specific power consumption was found to be 2/3 of that in the stirred vessel.
Evolutionary biotechnology – theory, facts and perspectives
Authors: Schuster P. 
Published: December 2004

AbstractMolecular evolution has recently been applied in biotechnology which consist of the development of evolutionary strategies in the design of biopolymers with predefined properties and functions. At the heart of this new technology are the in vitro replication and random synthesis of RNA or DNA molecules, producing large libraries of genotypes that are subjected to selection techniques following DARWIN's principle. By means of these evolutionary methods, RNA molecules were derived which specifically bind to predefined target molecules. Ribozymes with new catalytic functions were obtained as well as RNA molecules that are resistant to cleavage by specific RNases. In addition, the catalytic specificities of group I introns, a special class of ribozymes, were modified by variation and selection.Efficient applications of molecular evolution to problems in biotechnology require a fundamental and detailed understanding of the evolutionary process. Two basic questions are of primary importance: (i) How can evolutionary methods be successful as the numbers of possible genotypes are so large that the chance of obtaining a particular sequence by random processes is practically zero, and (ii) how can populations avoid being caught in evolutionary traps corresponding to local fitness optima? This review is therefore concerned with an abridged account of the theory of molecular evolution, as well as its application to biotechnology. We add a brief discussion of new techniques for the massively parallel handling and screening of very small probes as is required for the spatial separation and selection of genotypes. Finally, some imminent prospects concerning the evolutionary design of biopolymers are presented.
Immobilization of glucose oxidase and peroxidase to a urea derivative of granulated microcrystallized cellulose
Authors: Ivanov I. P. 
Published: December 2004

AbstractGlucose oxidase and peroxidase were immobilized individually to a urea derivative of granulated microcrystallized cellulose activated by formaldehyde. The catalytic properties of the immobilized enzymes were studied and compared to those of the soluble enzymes. The immobilized glucose oxidase and peroxidase were used for the manual determination of the concentration of glucose in sera. The developed method is characterized by high analytical reliability and comparatively low cost. The results correlated well with those obtained by using a BECKMAN glucoanalyzer, utilizing soluble glucose oxidase.
Cloning and expression of the porA gene of the Neisseria meningitidis strain B : 4 : P1.15 in Escherichia coli. Preliminary characterization of the recombinant polypeptide
Authors: Guillen G. , Alvarez A. , Niebla O. , Silva R. , Gonzalez S. , Musacchio A. , Martin A. , Delgado M. , Herrera L. 
Published: December 2004

AbstractThe gene coding for the class 1 outer membrane protein from the Neisseria meningitidis strain B385 (B : 4 : P1.15) was isolated by the Polymerase Chain Reaction (PCR) and cloned into the Sma I cut M13mp 18 vector. Then, a Xba I restriction site was created by using an oligonucleotide‐directed in vitro mutagenesis system at the start of the coding fragment. In order to express the protein, this fragment was fused to 180 base pairs corresponding to 60 amino acids from the N terminus of interleukin‐2 under the control of the tryptophan promoter (Ptrp). The expression was confirmed by Western‐blotting where the recombinant protein (PILM28) was detected by bactericidal monoclonal antibodies (MABs). The recombinant polypeptide was partially purified and used to elicit murine antibodies, able to recognize the meningococcal class 1 subtype 15.
The use of a thermotolerant fermentative Kluyveromyces marxianus IMB3 yeast strain for ethanol production
Authors: Banat I. M. , Singh D. , Marchant R. 
Published: December 2004

AbstractAn investigation was carried out on the growth and ethanol production of a novel thermotolerant ethanol‐producing Kluyveromyces marxianus IMB3 yeast strain. It grew aerobically on glucose, lactose, cellobiose, xylose and whey permeate and fermentad all the above carbon sources to ethanol at 45°C. This strain was capable of growing under anaerobic chemostat fermentation conditions at 45°C and a dilution rate of 0.15 h−1 and produced ≤ 0.9 g/l biomass and 1.8% (v/v) ethanol. An increase in biomass (up to 10.0 g/l) and ethanol (up to 4.3% v/v at 45°C and 7.7% v/v at 40°C) were achieved by applying a continuous two‐stage fermentation in sequence (one aerobic and one anaerobic stage) or a two‐stage anaerobic fermentation with cell recycling. Potential applications, involving alcohol production systems, for use in dairy and wood related industries, were discussed.
Heavy metal sorption by microalgae
Authors: Sandau E. , Sandau P. , Pulz O. 
Published: December 2004

AbstractViable microalgae are known to be able to accumulate heavy metals (bioaccumulation). Against a background of the increasing environmental risks caused by heavy metals, the microalgae Chlorella vulgaris and Spirulina platensis and their potential for the biological removal of heavy metals from aqueous solutions were taken as an example for investigation. Small‐scale cultivation tests (50 1) with Cd‐resistant cells of Chlorella vulgaris have shown that approx. 40% of the added 10 mg Cd/l was removed from the solution within seven days. At this heavy metal concentration sensitive cells died.Non‐viable microalgae are able to eliminate heavy metal ions in a short time by biosorption in uncomplicated systems, without any toxicity problems. Compared with original biomasses, the sorption capacity of microalgal by‐products changes only insignificantly. Their low price makes them economical.
Modelling the stability of the pBR322 plasmid derivative pBB210 in Escherichia coli TG1 under non‐selective and selective conditions
Authors: Löser C. , Ray P. 
Published: December 2004

AbstractA mathematical model has been developed to describe the stability behaviour of the pBR322 plasmid derivative pBB210 with the β‐lactamase gene and the human interferon‐α1 gene in Escherichia coli TG1 under non‐selective, selective and modified selective conditions in a chemostat. The model was formulated on the basis of experimental investigations. It includes the interaction between β‐lactam antibiotics (ampicillin and sulbactam) and cells (with and without plasmids), in particular the correlation between the growth rate of plasmid‐free cells and ampicillin concentration in the medium; ampicillin transport into the periplasm of the plasmid‐bearing cells; ampicillin degradation in the periplasm by by plasmid‐encoded β‐lactamase and the inhibition of the latter by sulbactam.The results obtained by the simulation of chemostat cultivations under various conditions and by steady state analyses are closely related to the results of experiments. Under non‐selective conditions, the fraction of plasmid‐bearing cells was approaching zero. Under selective and modified selective conditions, a coexistence between plasmid‐free and plasmid‐bearing cells was reached at steady state. Under these conditions, the steady state fraction of plasmid‐bearing cells was proportional to the ampicillin concentration in the feed and inversely proportional to the cell concentration in the chemostat. During high‐density cultivation, a large amount of ampicillin is necessary to suppress plasmid‐free cells. Even small concentrations of the β‐lactamase inhibitor sulbactam in the feed increased the steady state fraction of plasmid‐bearing cells (from 17.2% to 99.6% at sulbactam‐Na concentrations of 0 to 5 mg/l).
Degradation of sugar cane bagasse by several white‐rot fungi
Authors: Breccia J. D. , Siñeriz F. , Bettucci L. , Piaggio M. 
Published: December 2004

AbstractForty‐two white‐rot fungi isolated in South America were incubated with long fibre sugar cane bagasse (LFB). The residual composition of LFB was determined after white‐rot decay at 30 and 60 days. The ratio of residual lignin to residual lignin to residual cellulose (RL/RC) of untreated material (LFB) was 0.48. After white‐rot‐decay, the residual material with lower RL/RC ratios indicated that mainly lignin was degraded. In only 30 days,Phlebiasp. MVHC 5535,Atheliasp. MVHC 5509 andSpongipellis pachyodonMVHC 5019 caused a decrease in the RL/RC ratio to 0.36, 0.37 and 0.38, respectively, while it took 60 days forGanoderma applanatumMVHC 5347,Hyphodontiasp. MVHC 5544,Panus tigrinusMVHC 5400,Stereumsp. MVHC 5113,Phellinus punctatusMVHC 5346 and MVHC 6388 to reach a ratio lower than 0.40. No correlation was found between the amount of some ligninolytic enzymes secreted and the residual composition of bagasse after white‐rot fungi fermentation. Most of the fungal strains caused an increase in the relative amount of residual cellulose, indicating that hemicellulose was the preferred energy source.
α‐Galactosidase in immobilized cells of Papaver somniferum L.
Authors: Stano J. , Nemec P. , Kovács P. , Kákoniová D. , Lišková D. , Neubert K. 
Published: December 2004

AbstractA poppy cell suspension culture was permeabilized by Tween 80 and immobilized by glutaraldehyde. The α‐Galactosidase in these cells showed an optimum pH level at 5.2 and an optimum temperature at 70 °C. Enzyme hydrolysis was linear for 3 h, reaching 86% conversion. A very good level of storage stability was achieved when using dry catalyst and immobilized cells in 0.15 M NaCl solution (with the addition of chloramphenicol, [1‐methyldodecy1)‐dimethylamin‐4‐oxide (ATDNO), chlortetracycline hydrochloride (CLCTC)] or by freezing them in 0.15 M NaCl solution.