bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of ensiling on the nutritive value of low quality roughage rice hulls. II. Chemical studies
Authors: El‐;Sayed O. H. , Shawky B. T. , Zaki D. A. , Mouafi F. 
Published: December 2004

AbstractThe sequence of the effects of delayed and immediate sealed silos as well as the role of nutrient additives such as molasses and/or urea in the ensiling process of rice hulls and the subsequent nutritive value of the product has been shown.There were considerable variations in the chemical constituents during the ensiling of rice hulls among the different treatments under both delayed and immediate sealed silos. In all cases, when compared with the controls, the crude protein, soluble sugars, lactic acid, and fat contents were markedly increased, while the carbohydrate polymers and silica contents were significantly decreased. It was concluded that the treatment of rice hulls + 2% molasses for two months ensiling period under anaerobic conditions can be considered as the optimum conditions for the production of good quality silage from the low grade roughages rice hulls. Changes in pH values also confirmed the improving effect of the combination of molasses addition and the immediate sealing of the silos.
Factors in single‐cell protein production from pawpaw fruit pulp extract
Authors: Enwefa C. , Ayanru D. K. G. , Obuekwe C. O. 
Published: December 2004

AbstractMaximum production of single‐;cell protein (SCP), biomass, chemicals or fuels from microorganisms demands the manipulation of environmental conditions. Consequently, single‐;cell protein production was carried out using Candida sp. and pawpaw fruit pulp extract (substrate), under conditions of varying initial inoculum, different agitation rates, nitrogen sources, and heat treatments. The highest viable cell count of 8.00 ± 1.34 × 1010 colony forming units (cfu)/ml was obtained with substrate supplemented with ammonium sulphate and the least viable cell count of 7.10 ± 2.10 × 106 cfu/ml was observed using urea treated substrate. An optimum viable cell count occurred with an initial inoculum of 5.60 × 105 cfu/ml, conditions of non‐sterilization and agitation at 200 r.p.m. Growth also peaked at 24, 48 and 72 h with varying treatments.
Ultrafiltration of enzyme solutions by means of blood dialyzers
Authors: Luther H. , Hirsch S. , Schuster E. , Balfanz F. , Weber E. 
Published: December 2004

AbstractHollow fibres with a symmetrical pore structure as used in artifical kidneys are tested for other purposes. The modules are shown to be suitable for the processing of enzymes such as thermitase, penicillin acylase, uratoxidase, and phosphatase by means of ultrafiltration and diafiltration.These hollow fibre modules are compared with other modules used in laboratory or in small technical devices. Similar values and material transfer coefficients are calculated.
Continuous production of ligin peroxidase by phanerochaete chrysosporium immobilized on a sintered glass carrier
Authors: Rogalski J. , Dawidowicz A. L. , Wojtas‐Wasilewska M. 
Published: December 2004

AbstractPhanerochaete chrysosporium cells were immobilized on the sintered porous glass support. Such a biocatalizer was used as a bed of the enzymatic reactor system for the continuous production of lignin peroxidase. From the after culture fluid the lignin peroxidase enzymatic activity was recovered and purified applying anion exchangers. Additionally, some physico‐chemical properties of lignin peroxidases were determined.
Bench‐scale calorimetry – application in biotechnology
Authors: Zentgraf B. 
Published: December 2004

AbstractTwo calorimetric techniques are described allowing us to monitor and control microbial processes at relatively high cell densities: dynamic and continuous calorimetry. These techniques have been applied to study microbial systems, e.g. the dependence of thermodynamic efficiency and heat yield on specific growth rate, the heat yield of mesophilic and thermophilic microorganisms, the oxy‐caloric coefficient during aerobic microbial growth, as well as the energetics of the yeast‐cell cycle. Such studies are of importance for optimizing biotechnical processes.
Bisource carbon dioxide feeding of the photosynthetic process of microalgae autotrophic cultivation
Authors: Sokolov K. , Anguelov S. 
Published: December 2004

AbstractThe mechanism of carbon dioxide saturation of alkaline nutrient medium for the purpose of autotrophic cultivation of microalgae is studied. Carbon dioxide desorption from aqueous solutions of sodium hydrocarbonate is investigated and the influence of chemical equilibria in the solutions on the cultivation of carbon dioxide supply is discussed. It is pointed out that these solutions can be considered to be carriers of the assimilable carbon source for the microalgae cultivation, most efficient at pH 8.5. A comparative estimation of the carbon dioxide and the hydrocarbonic ion as assimilable components of the chemical equilibria under study was done, leading to the conclusion that the more probable component in an alkaline medium autotrophic microalgae cultivation is carbon dioxide. A scheme of bisource feeding of the photosynthetic process, with carbon dioxide for the autotrophic microalgae cultivation in a alkaline nutrient medium, providing a stable and economical cultivation process, is proposed.
Immobilized pectolytic enzymes on acrylic supports
Authors: Maxim S. , Flondor A. , Pasa R. , Popa M. 
Published: December 2004

AbstractThe paper deals with the pectolytic enzymes immobilization on different acrylic supports, and the application of immobilized preparations in the apple juice pectinization process.The correlation between the protein content (Cp) and specific catalytic activities of immobilized enyzme preparations suggest a specific immobilization process only in the case of PONILEX ASH type acrylic supports.The active immobilization degree on PONILEX ASH type supports of Ultrazym 100 G and technical pectinase extract ranged from 99.80 to 296.40% for the Pectinesterase (PE) activity, and from 101.85 to 252.94% for the chain splitting (CS) activity, proving that the ionic immobilization process is a selective one. The simulated operational stability of the immobilized pectolytic enzymes tested by the PE and CS activity values proves the preservation of enzyme catalytic activity.
Phenomenological principles of microbial lignin degradation
Authors: Härtig C. , Lorbeer H. 
Published: December 2004

AbstractThis paper intends to focus the attention to characteristic features of microbial lignin degradation from the phenomenological point of view. Six fundamental principles are discussed under special consideration of white‐rot fungi. The necessity of mycelial growth and the formation, secretion, and extracellular action of peroxidases are main requirements for a successful microbial attack on polymeric lignin.
The volumetric oxygen mass transfer coefficient in antibiotic biosynthesis liquids
Authors: Gavrilescu M. , Roman R. V. , Efimov V. 
Published: December 2004

AbstractThis paper approaches the problem of oxygen mass transfer. This transfer is in antibiotic biosynthesis liquids produced by microorganisms belonging to the actinomycete and fungi classes, which exhibit a shear thinning non‐Newtonian rheological behaviour.The volumetric oxygen mass transfer coefficients in these liquids (kL ab) change during biosynthesis processes. The change is mainly due to rheological parameter modifications, such as increasing the consistency index (K) and decreasing the flow behaviour index (n). The values of kL ab were 3.0–6.5 times lower than those recorded in water, and their decreasing depended on the kL a values obtained without biological liquid and on the nature of fermentation broths, as well.Starting from experimental data, two correlations were established between kL ab and P/V,υSG and P/V,υSG, N, respectively. These correlations contain a dimensionless factor (ηam/ηg), which takes into account the rheological properties of the liquid phase and offers the possibility for a fast and sufficiently accurate estimation of kL ab. The empirical correlations developed in the paper correspond reasonably well with the relatively wide variety of experimental data, as in the model proposed by PEREZ and SANDALL, and allow for the comparison of the fermentation batches of the same or different microorganisms; also, they may be applied to the workings of design, scale‐up, control and monitoring of bioreactors.
Catabolic repression and microbial modelling for the yeast Saccharomyces cerevisiae
Authors: Subramanian T. V. 
Published: December 2004

AbstractThe mechanism of catabolic repression is not yet fully understood. Oxygen seems to control the level of cytochrome in the in situ state. The level of glucose seems to control other enzymes; glucose by itself does not repress the cataboism. An unidentified product of glucose metabolism is believed to be involved. In bacterial cultures, there is convincing evidence that cyclic AMP is involved and this operates at the levels of gene trancription. In yeast, it is not clear. The level of CAMP is found to be reduced with catabolic repressed cells, but there is little evidence to conclude that CAMP acts at the transcription level [1]. There are results to indicate that it acts at the translational level or enzyme activation phase in yeast. In order to understand this mechanism, the bioenegetics of yeasts grown under catabolic repression is analyzed with the data available [2] and appended.
Morphological characterization of microencapsulated Penicillium raistrickii i 477
Authors: Irrgang S. , Riemay K.‐H. , Schlosser D. , Schmauder H.‐P. 
Published: December 2004

AbstractFor the immobilization of spores of Penicillium raistrickii i 477 the formation of polyelectrolyte complexes using the sodium salt of cellulose sulphate as polyanion and poly‐dimethyl‐diallylammoniumchloride as polycation was used. Light and scanning electron microscopy have shown that during germination of spores the capsule walls do not cause effective limitations on hyphal growth and that there are no significant morphological changes of the mycelium detectable by an outgrowth of immobilized spores. By comparing the 15α‐hydroxylation of 13‐ethyl‐gon‐4‐en‐3,17‐dione with free and encapsulated cells it was found that an increase of total dry biomass per immobilized system led to a higher product formation in relation to free cells.
Single cell protein from bagasse pith by a mixed bacterial culture
Authors: Rodriguez H. , Gallardo R. 
Published: December 2004

AbstractA spontaneous association of Cellulomomas sp. with another bacterial strain was studied for its capabilities for single cell protein (SCP) production from bagasse pith. The associated strain was identified as Pseudomonas sp. and further characterized for its physiological properties. The effect of the initial proportions of both strains, the way of propagation, and the effect of pH on the growth of the mixed culture on bagasse pith was studied. Separate propagation of both strains before the fermentation step (“controlled mixed culture”), a range of proportions Cellulomonas‐Pseudomonas from 4:1 to 100: 1, and pH 7.0, were found to be the most appropriate conditions of growth. A mutualistic symbiotic relationship was demonstrated to take place between both strains during the mixed growth on bagasse pith, the Cellulomonas supplying the carbon source (glucose produced from bagasse degradation) to the Pseudomonas, and the latter producing the vitamin supplements necessary for the Cellulomonas growth, allowing the growth of the mixed culture in a minimal medium, without any growth factor supplement. Fed‐batch cultivation of the mixed culture on this substrate was successful, giving rise to high biomass production (19.4 g/l), thus increasing the productivity of the system. Due to its improved productivity, high biomass production, inexpensiveness of the culture medium, (without any vitamin supplement), and good stability, this culture presents economical advantages and constitutes an attractive choice for lignocellulosic substrate utilization.
The influence of energy deficiency‐imposing conditions on the capacities ofAcetobacter methanolicus to oxidize glucose and to produce gluconic acid
Authors: Loffhagen N. , Babel W. 
Published: December 2004

AbstractThe presence of dinitrophenol (DNP) during the chemostatic growth of Acetobacter methanolicuson glucose led to i) no significant increase in glucose dehydrogenase, ii) a decrease in the capacity to oxidize glucose by about 30%, not depending on the DNP concentration, and iii) a gradual decrease in the capacity to form gluconic acid, depending on the concentration of the uncoupler. Similar effects of DNP on Acetobacter methanolicuswere observed during the gluconic acid formation process. The loss in the capacity to form gluconic acid is indicated by a drop in the ATP concentration of the cells which cannot be counteracted by the ATP syntheses originating from the oxidation of gluconic acid and of glucose. ATP could be necessary for pumping protons out of the cells that were taken up together with gluconic acid and by the effect of DNP.
Degradation of aromatic compounds by Pseudomonas putida
Authors: Dluhý M. , Šefčík J. , Báleš V. 
Published: December 2004

AbstractThe influence of different process kinetics on the course of phenol degradation has been studied as well as the influence of axial dispersion in the liquid phase on the reactor height with relatively large biofilm thickness in a conventional fluidized bed and air‐lift bioreactor. The object of this was to achieve a high conversion of substrate in a device of real size in real process time. For calculating the mathematical model, the method of orthogonal collocation with the STIFF integration routine has been used.
Amyloglucosidase immobilized on acrylic supports
Authors: Maxim S. , Flondor A. , Bunia I. 
Published: December 2004

AbstractThis paper deals with the study of the behaviour of Amyloglucosidase covalently immobilized on acrylic supports in the maltodextrin hydrolysis process. The specific catalytic activity of the different immobilized Amyloglucosidase preparations critically depends on their protein content. The maltodextrin hydrolysis in the presence of the immobilized Amyloglusidase is a diffusion‐controlled process. The simulated operational stability of the immobilized Amyloglucosidase tested by the specific activity and the substrate conversion proves the conservation of the catalytic enzymatic activity.
L‐Phenylalanine production by double auxotrophic analogue resistant mutants of Arthrobacter globiformis
Authors: Maiti T. K. , Catterjee S. P. 
Published: December 2004

AbstractA number of tryptophan plus tyrosine double auxotrophic mutants isolated by the NTG treatment of a glutamate producing strain of Arthrobacter globiformis were found to excrete phenylalanine in a mineral salt medium. By controlling the pH of the medium to near neutrality, the active growth period could be extended up to 72 h and more phenylalanine was accumulated compared to the unregulated culture where the growth period took up to 48 h. Under optimum culture conditions, the best double auxotroph (TT‐39) produced 3 g phenylalanine/l. Further improvement of phenylalanine production has been achieved by the step‐by‐step isolation of a mutant resistant to the phenylalanine analogues p‐fluorophenylalanine (PFP) and β‐2‐thienylalanine (TA) from the TT‐39 strain. Under optimum culture conditions, the best double auxotrophic analogue resistant mutant TT‐39 PTr‐21 yielded 8.7 g/l phenylalanine.
Fermented tempeh‐like products as useful way of utilizing legume seeds
Authors: Piskorz B. J. , Nowak J. , Szebiotko K. 
Published: December 2004

AbstractThe in vitro effect of fermented tempeh‐like food on intensive flatulence caused by intestinal bacteria after consuming soybeans (Glycine max) was studied.Six fungi strains of Rhizopus and Actinomucor were tested. Rhizopus oligosporus NRRL 2710 proved to have the highest antibacterial activity. In vitro tests vs. Clostridium perfringens 546 showed that the soybean extract from the food fermented with the fungi mentioned above in about 80% of the experiments slowed the bacterial growth rate remarkably. The homogenization of tempeh‐like food increased its antimicrobial activity. Cultures of Rh. oligosporus NRRL 2710 grown on the brewery wort medium did not show any antibacterial activity.
Investigations of subtilisin (Novo type) immobilization on cellulose by means of various methods of support activation
Authors: Trzmiel T. , Galas E. , Fortak M. 
Published: December 2004

AbstractThe immobilization of subtilisin, Novo type, on WHATMAN cellulose activated by the glutaraldehyde, diisocyanate, diazo‐coupling, and S‐triazine method, and on a dialdehyde derivative of cellulose has been studied. The best results of proteinase immobilization were achieved when cellulose was activated by hexamethylene diisocyanate. The preparations of a proteolytic activity of 70 PU/g of support and of an esterase activity of 2.3 EU/g of support were obtained with 14% and 38% yield, respectively.
Fractionation of dextran solutions by cross‐flow filtration
Authors: Michelena G. , Bell A. , Rivas E. M. 
Published: December 2004

AbstractThe use of ultrafiltration to fractionate dextran solutions in order to obtain fractions for the synthesis of dextran derivatives was investigated.Several experiments were carried out in two available commercial ultrafilters. The operation was evaluated by the recovery yield and process time.Dextran solutions can be fractionated being concentrated up to 9 fold in a PM30, but no more than double in a PM5 hollow fibre membrane cartridge.
Growth control and ppGpp synthesis in Brevibacterium flavum cells at various medium mixing rates and aeration intensities
Authors: Ruklisha M. , Labane L. , Viesturs U. 
Published: December 2004

AbstractUnder the conditions of various aeration and medium mixing intensities (even at a constant medium oxygen partial pressure value), the variations in the RNA synthesis as well as the growth rate of lysine producing Brevibacterium flavum strains are inversely correlated with the ppGpp concentration in the cells.An increase in the ppGpp synthesis and a decrease in the RNA content in the cells was observed in the cases of a low cell energy charge value (lower than 0.6). This took place in the cases of bacterial cultivation at a low or very high medium aeration and mixing intensity. Hence, the energy production in the cells, the ppGpp synthesis and the growth control mechanism in Corynebacteria may be regarded as connected processes.
Degradation of synthetic lignin by the protoplasts of Phanerochaete chrysosporium in the presence of lignin peroxidase or manganese peroxidase
Authors: Sayadi S. , Odier E. 
Published: December 2004

AbstractLignin was mineralized in the experiments in which 14C‐lignin was incubated with lignin peroxidase or manganese peroxidase in a tartrate buffer in the presence of cycloheximide‐treated protoplasts obtained from the ligninolytic mycelia of Phanerochaete chrysosporium. The rate of lignin mineralization was dependent on the lignin peroxidase or manganese peroxidase concentration in the medium. In the experiments in which lignin was incubated with lignin peroxidase or manganese peroxidase, lignin was repolymerized irrespective of the presence of protoplasts mineralizing lignin, suggesting that an active degradation of lignin and repolymerization took place. Taking into account that lignin peroxidase and manganese peroxidase were the only extracellular enzymes in the experiments in which lignin was mineralized by the protoplasts, it is postulated that lignin peroxidase and/or manganese peroxidase can degrade lignin into small fragments which can then be further absorbed by the fungal cells and subsequently degraded to CO2.
Cloning and expression of the Neisseria meningitidis 5C outer membrane protein
Authors: Guillen G. , Leal M. J. , Alvarez A. , Delgado M. , Silva R. , Herrera L. 
Published: December 2004

AbstractThe 5C outer membrane protein, one of the N. meningitidis class 5 proteins, was preferably expressed in bacteria isolated from the nasopharynx and its role in adhering to the mucosal cells and invading them as well as the development of anti‐5C antibodies in healthy carriers was demonstrated. Anti‐5C monoclonal antibodies are bactericidal in the presence of the human complement. The immunodominant region of the 5C protein is highly conserved among the different strains of N. meningitidis, and the opc gene, which encodes the protein, does not seem to show antigenic variations.Here the isolation of the opc gene from the Cuban strain B:4:P1.15 by PCR (Polymerase Chain Reaction) is presented. Under the regulation of the tryptophan promoter, the gene was cloned and sequenced in E. coli with a high level of expression and fused to the amino‐terminal end of the interleukin‐2 gene. In the dot‐blot experiments, the presence of the gene in those strains which did not express the protein in the whole cell ELISA was also detectable.
Continuous semi‐solid cultivation for the production of cellulase by Trichoderma reesei mutants using a polyurethane foam carrier and a liquid medium
Authors: Targonski Z. , Pielecki J. 
Published: December 2004

AbstractThe production of cellulase was investigated in semi‐solid state culture using the immobilized mycelium of Trichoderma reesei mutants on polyurethane foam impregnated with lactose medium. An extremely high value of about 2.6 FPU/ml was reached after the cultivation of T. reesei D‐78085 on a 0.5% lactose medium in continuous culture at a pH medium of 4.0 when a bioreactor with vertical polyurethane foam plates was used. The enzyme yield on lactose was 520 FPU/g of lactose metabolized in comparison with 160 FPU/g using a stirred tank bioreactor.
Stability of the pBR322 plasmid derivative pBB210 in Escherichia coli TG1 under non‐selective and selective conditions
Authors: Löser C. 
Published: December 2004

AbstractThe stability behaviour of the pBR322 plasmid derivative pBB210 with β‐lactamase gene and human interferon‐α1 gene in Escherichia coli TG1 was studied in chemostat cultures under non‐selective (medium without antibiotics), selective (medium with β‐lactam antibiotic ampicillin) and modified selective (medium with ampicillin and the β‐lactamase inhibitor sulbactam) conditions. Under non‐selective conditions, a behaviour typical of unstable systems was found. Under selective conditions, the behaviour predicted by the models was obtained – the fraction of plasmid‐bearing cells in the population approached a constant value which was dependent on the ampicillin concentration in the feeding and on the cell concentration in the chemostat. Under modified selective conditions, the higher the concentration of sulbactam in the medium was, the higher the fraction of plasmid‐bearing cells was in steady state conditions.