bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimization of solid‐state fermentation of citrus dried peel by aspergillus niger in a packed bed column
Authors: Rodriguez J. A. , Bechstedt W. , Echevarria J. , Sierra N. , Delgado G. , Daniel A. , Martinez O. 
Published: December 2004

AbstractThe protein enrichment of citrus dried peel on solid‐state fermentation by Aspergillus niger in packed bed column was optimized using a two factor central composit design with α = 2 considering the “initial moisture content of the fermentation mass” and the “temperature in the centre of the fermenter”. It results significance for the moisture content (optimum 56%) and non significance for the temperature in the conditions employed. This indicates that a considerable range of temperature increase for the investigated SSF system could be allowed.
Theoretische Grundlagen des Auxiliarsubstratkonzeptes und seine praktischen Konsequenzen in biotechnischen Prozessen
Authors: Babel W. 
Published: December 2004

AbstractRaw materials for microbial synthesis of single cell protein and metabolites are chemo‐heterotrophic substrates. The growth and product yields are economically very important parameters. Therefore it is necessary to look for methods to optimize these biotechnological processes, i. e. to increase these values up to the theoretically possible limits.In the SCP production the growth yield is determined energetically and in the overflow production the yield is influenced by the amount of biologically useful energy which is produced during the product synthesis.It is demonstrated that the auxiliary substrate concept is appropriate to improving the yield both for SCP‐ und product synthesis.In the SCP synthesis two (or more than two) substrates must be mixed that way that the biologically useful energy, which is generated along the way from substrates to a central precusor for the cell substance synthesis, becomes a maximum thus no further substrate need to be oxidized merely for the purpose of energy generation.By using a substrate, which operates only as an energy donor in the mixture the carbon metabolism determined upper limit of the carbon conversion efficiency can be attained.For with the overflow production of metabolites the biologically useful energy seems to be responsible for the discrepancy between the metabolism‐determined product yield and the experimentally obtained one, the energy liberated during the production of primary metabolites must be kept low.This might be reached by using substrate mixtures.Furthermore it is shown that in this way the specific production rate can be improved as well.
Anreicherung von Cadmium in Biomassen
Authors: Gwenner Chr. , Wittig H. , Glombitza F. 
Published: December 2004

AbstractThe uptake of cadmium ions from an aqueous solution by living, resting, and dead biomasses was investigated. The dependence of the uptaked amounts on pH‐value of the medium, temperature and concentration of cadmium ions is demonstrated as well as the rate of uptake.Maximum realisable concentrations were 12 mg/g biomass in living cells and about 20 mg/g biomass in resting or dead cells, respectively.
Exogenous cellulases of thermophilic micromycetes. II. Thermostability of enzyme preparations
Authors: Kvesitadze G. , Gogilashvili L. , Svanidze R. , Buachidze T. , Chirgadze L. , Nizharadze D. 
Published: December 2004

AbstractThe ability of a large number of higher fungi to form extracellular cellulases is investigated. Some representatives of these fungi grow at 40–50°C, and form extracellular cellulases exceeding cellulases of mesophilic fungi in thermostability. It is shown that cellulases of higher thermophilic fungi differ by their thermostability. The temperature optimum of cellulase action of higher fungi occurs within 60–62°C.
Oil feeding during the oxytetracycline biosynthesis
Authors: Ettler P. 
Published: December 2004

AbstractThe ability of utilization of vegetal oils belongs to common properties of Streptomycetes. During the cultivation of Streptomyces rimosus and biosynthesis of oxytetracycline in 15 m3 fermenters, a fixed regime of soya bean oil feeds as antifoam agent and partial carbon source according to subjectively designed mechanism was investigated and further also feeding regime after exhausting starch as main carbon source and finally his dosing with ammonia sulphate in accordance with physiological activity of the culture. In the second case with semicontinuous supplements of soya bean oil it was possible to prevent premature autolysis of mycelia and to extend the biosynthetic process with keeping the oxytetracycline production rate. The third approach, the most progressive one, represents besides the automatisation of control loop the necessity of assurance continuous pH adjustment for elevation of the process production rate.
Studies on biosynthesis of hydrolases by trichoderma sp. M7 on submerged and solid‐state cultivation conditions
Authors: Atev A. P. , Panayotov Ch. A. , Bobareva L. G. , Damyanova L. D. , Nicolova U. D. 
Published: December 2004

AbstractThe biosynthesis of cellulases and xylanase by the mould strain Trichoderma sp. M7 on submerged and solid‐state cultivation conditions has been studied. The effect of different inducers on the enzyme biosynthesis on the conditions used was determined. The relation between the enzyme biosynthesis and the morphological state of the producing strain was studied. The advantages of the submerged cultivation conditions with regards to the efficiency of the enzyme inducer are shown.
Selection of distiller's yeasts with particular respect to non‐saccharomyces strains
Authors: Laube K. , Wesenberg J. , Lietz P. 
Published: December 2004

AbstractThe investigations demonstrate that in addition to Saccharomyces also strains Candida and Hansenula can be used for ethanol production. Their efficiences are at the standard level and the first phase of fermentation is considerably accelerated with results in suppression of bacterial contamination in cold mashing. In the future efficiency optimisations will be expected based on mixed strain populations as well as on technological improvement. Furthermore, genetic modifications present actually a real prospect to secure “made‐to‐measure” strains for special processes of corn mash fermentation.
Comparative trace element and organic growth factor requirements of five hansenula species
Authors: Kamra N. , Madan M. 
Published: December 2004

AbstractA comparative response of specific trace elements and organic growth factors for the growth of five Hansenula species (H. anomala, H. beijerinckii, H. ciferrii, H. polymorpha and H. sydowiorum) has been studied. Out of twenty three trace elements tested, Fe, Zn, Mn and Cu were found to be essential for the growth of all yeast species studied here, whereas the rest of the elements exhibited variable essentiality. From fifteen organic growth factors tested, thiamine, biotin, pyridoxine and inositol are the most commonly required growth factors by the yeasts, whereas the rest of the organic growth factors showed variable essentiality. All species of yeasts investigated required different concentrations of trace elements and organic growth factors for their optimum growth. Concentrations higher than the optimum have been found to be inhibitory for the growth of all the yeasts studied.
Einfluß von Lipidfraktionen mikrobieller Herkunft auf die Wasserausnutzung in der biologissechen Stoffproduktion von Kulturpflanzen
Authors: Bergmann H. , Voigt B. , Seidel H. , Meisgeier G. 
Published: December 2004

AbstractEffects of exogenous applied lipids being of microbial origin on the water use efficiency (WUE) and the biomass production have been studied in pot and field experiments using crop plants.Lipid mixtures extracted from the cells of Candida maltosa EH 15 increased the WUE (9…16%) and the grain yield (÷x = 10%) of the wheat and barley plants under dry conditions. The fatty acid fraction separated from the lipid mixtures also improved the WUE especially under stress (20…100%) and the biomass production. The phosphatide fraction emulsified with sulfonate containing solvents was not physiologically active.
Rolle der n‐Alkane in Melasse‐Nährmedium beim Oberflächenverfahren der Citronensäurefermentation
Authors: Żzakowska Z. , Druri M. 
Published: December 2004

AbstractThe investigation of unfitness of beet molasses for citric acid production shows the presence of hydroacarbons in a toxic fraction of lipid extracts derived from antifoaming agents used in the suger industry. The model experiments demonstrate that these compounds dispersed in water solutions of the medium create on the surface of growing spores a layer which isolates them from the surrounding and prevents their normal growth. The inhibition effect of hydrocarbons on Aspergillus niger increases with degree of their dispersion in the water phase and is promoted by surface active substances e.g. emulgators present in antifoaming additives.
Use of heterotrophic microorganisms in mineral biotechnology
Authors: Groudev S. N. 
Published: December 2004

AbstractA process for biological removal of iron from quartz sands, kaolins and clays was developed in which these industrial minerals were leached at 90°C with lixiviant produced as a result of the cultivation of acid‐producing heterotrophic microorganisms, mainly strains of Aspergillus niger, at 30°C in a nutrient medium containing molasses as a source of carbon and energy. The lixiviant, i.e. the fermentation fluid, contained oxalic and citric acids as main components and after the cultivation was acidified to a pH of 0.5 by means of hydrochloric acid. The leaching was carried out in mechanically stirred acid‐resistant vats for a period of from 1 to 5 hours. The iron content of some sands treated by this method was lowered from 0.035–0.088 to below 0.012% Fe2O3 making them suitable for the preparation of high quality glass. The iron content of different kaolins was lowered from 0.65–1.49 to 0.44–0.75% Fe2O3 and as a result of this their whiteness was increased from 55–87 to 86–92%. The iron content of a clay was lowered from 6.25 to 1.85% Fe2O3 and this increased the fireproofness of the clay from 1 670 to 1 750°C. Similar process was used for leaching of aluminium from aluminosilicates, mainly clays and kaolins. However, after the cultivation the fermentation fluid was acidified either by means of sulfuric or hydrochloric acid or by means of different mixtures of inorganic acids. For enhancing aluminium solubilization the aluminosilicates were heated before leaching at 600–650°C for 1–2 hours. Over 90% of the aluminium present in different clays and kaolins was leached within 3–6 hours in this way.“Silicate” bacteria related to the species Bacillus circulans and B. mucilaginosus were used to leach silicon from low‐grade bauxite ores containing aluminosilicates as impurities. The bacterial action was connected with the formation of mucilaginous capsules consisting of expolysaccharides. The solid residues after leaching were characterized by higher values of alumina content and were suitable for processing by means of the BAYERprocess for recovering aluminium.Heterotrophic bacteria were used to leach manganese from oxide ores using different organic compounds as reducing agents.
Gasometric measurement of sulfite oxidation
Authors: Nikolajewski H. E. , Liepert H. 
Published: December 2004

AbstractIn the commonly used sulfite method the consumption of sulfite is determined by iodometry. Since however, the addition of organic substances may interfere with iodometry (e.g. due to chemical reactions with iodine) the gasometric measurement of sulfite oxidation has been developed for analysis of how different culture media may influence the oxygen transfer rate. The striking decrease of sulfite oxidation rate due to addition of culture media to the sulfite solution suggests that adsorption of orgnic components in the gas liquid interface may account for an additional diffusion barrier and thus for a decrease of the oxygen transfer coefficient which in addition gives an explanation for differences between values found by the sulfite method and by aerobic cultivations. Consequently identical values of oxygen transfer rate have been obtained for both systems whenever the sulfite system has been properly adjusted to the aerobic cultivation conditions. In so far, the gasometric sulfite method proved to be a unique tool for rapid determination of factors influencing oxygen transfer rate in fermentation processes which may give rise to a reappraisal as to the relevance of the sulfite method for oxygen transfer optimization.
Enzymelektrode zur Bestimmung von L‐Lysin in Aminosäuregemischen
Authors: Weissbach F. , Schindler W. , Huber J. , Kreibich G. 
Published: December 2004

AbstractA specific enzyme electrode with L‐Lysine decarboxylase (E.C. 4.1.1.18) from Klebsiella pneumoniae and a CO2‐sensor are described. The electrode can be used for assay of L‐Lysine in amino acid mixtures as protein hydrolysates or culture filtrates from fermentation processes. The accuracy and reproducibility are those of an amino acid analyzer. The electrode works well for several weeks.
Laugung lateritischer Nickelerze mit heterotrophen Mikroorganismen
Authors: Bosecker K. 
Published: December 2004

AbstractOrganic acids that are excreted by microorganisms dissolve nickel from lateritic ores. In chemical leaching experiments, fifteen organic acids were tested in the concentration range of 0.05–0.5 M. The most effective were hydroxycarboxylic acids. The leaching of nickel is dependent on the type of mineralization. With completely limonitized ore, no mobilization occurred, while up to 90% of the nickel was extracted from silicate‐bearing laterites by 0.5 M citric acid.In biological leaching tests, Penicillium was found to be the most effective microorganism. After improvement of the leaching conditions, up to 70% of the nickel was extracted at considerably lower citric acid concentrations than with the chemical leaching process. Generally, leaching of nickel from lateritic ores with heterotrophic microorganisms is possible and seems to be promising. Possibilities for future investigations are discussed.
Induction of cellulase in trichoderma reesei grown on lactose
Authors: Farkaš V. , Šesták S. , Grešíak M. , Kolarova N. , Labudová I. , Baucer Š. 
Published: December 2004

AbstractIntracellular concentrations of ATP, cyclic AMP and glucose‐6‐phosphate were monitored during growth of partially catabolically derepressed strain of Trichoderma reesei CC II in medium containing lactose as the sole carbon source. The induction of cellulase synthesis occured when the concentration of lactose in the medium decreased below 7 mg/ml. The onset of cellulase synthesis was preceded by a transient peak of intracellular concentration of ATP and by the increase of the cyclic AMP contents in the mycelium whereby the intracellular level of glucose‐6‐phosphate was at its minimum. By keeping the lactose concentration in the medium at 2 mg/ml, it was possible to support the continuation of cellulase synthesis over the prolonged periods without appreciable growth of biomass.
Verbesserung alter biotechnologischer Verfahren
Authors: Schügerl K. 
Published: December 2004

AbstractBy the example of the Penicillin G production, it is shown, how the production process can be improved by using pellet suspension instead of highly viscous filamentous mycel. In order to optimize the pellet geometry, dissolved oxygen concentration profiles were measured, and the overall mass transfer resistance was calculated in the pellets; histological investigations were carried out with pellets also. All measurements indicated that the optimal pellet diameter is 400 μm. When using this pellet, the specific power input was reduced from 4–5 kW/m3 to 0.8 kW/m3. The losses during the recovery of Penicillin G can be reduced below 1% by using reactive extraction. The thermodynamics, kinetics and reaction technique of reactive extraction of Penicillin G are also taken into account.
Nutzung cellulosehaltiger Abprodukte bei der Biosynthese von Cellulasen
Authors: Pobedimskij D. G. , Mukmenev I. E. , Savdur V. I. , Liakumovic A. G. , Agadganjan S. I. 
Published: December 2004

AbstractIt was analysed the influence of different pretreatment methods of cellulosic materials to increase the productivity of the cellulase biosynthesis.The most effective pretreatment method for cotton cellulose is the thermomechanical destruction in a worm extruder (5–15 minutes) with hydrolysis catalysts.The enzymatic saccharification degree was increased about 4 fold. Utilizing a pretreated cellulose an increase of 70–120% in C1‐activity was found besides their level was stabilized in higher values.It was demonstrated that enzymatic hydrolysis parameters would be applied as model for biochemical utilization of cellulosic materials in the biosynthesis of cellulases.
Biotechnologische Produktion mikrobieller Wirkstoffe: ein Beispiel für die Nutzung des Adaptationspotentials von Mikroorganismen
Authors: Gräufe U. 
Published: December 2004

AbstractThe role of the microbial secondary metabolism in the cytodifferentiation of producer strains and in the ecological system is reviewed. The production of bioactive metabolites such as antibiotics seems to play a role in long‐term strategies of adaptation to environmental changes. This is reflected by characteristic features of regulation of the secondary metabolism such as catabolite repression, lack of uniform regulatory mechanisms and limited specificity of enzymes involved. The examples given may show that advantages have been taken from the knowledge of special regulatory features with regard to strain improvement and the designing of the metabolite spectrum.
Effects of temperature on microbial ethanol production. III. The influence of the temperature on the relation existing between the specific ethanol formation rate of the yeast Saccharomyces cerevisiae Sc 5 and the ethanol concentration in the culture medium
Authors: Richter K. , Becker U. 
Published: December 2004

AbstractThe ethanol‐inhibitory behaviour of the yeast Saccharomyces cerevisiae Sc 5 was found to be characterized by a continual‐linear relation between the specific ethanol formation rate and the ethanol concentration. Therefore the simple equation

could be applied for it.It is shown that this model is correct only then, if all of the process parameters are in their optimum.Out of the optimum temperature range the characteristics of the function ν = f(P) change in such a way that in regard to the ethanol concentration P twc linear relations exist for each suboptimum temperature:

and a non‐linear equation is current for each superoptimum temperature:

where bT is also a function of the temperature and always less than 1.Taking as a basis these equations the specific ethanol formation rate of the used strain can be calculated for the whole biokinetic P/T‐sphere of ethanol production.
Production of ethanol from cassava whey
Authors: Akpan I. , Uraih N. , Obuekwe C. O. , Ikenebomeh M. J. 
Published: December 2004

AbstractInvestigations were conducted into the potential use of enzyme hydrolysed cassava whey for ethanol production by Saccharomyces cerevisiae Aspergillus niger grown on whct bran was used as crude enzyme source to saccharify the whey starch. The whey with an initial HCN concentration of 54.0μg/ml was fermented at pH 4.5 and 30°C in a one‐step process to produce ethanol. A maximum ethanol concentration of 4.5% (v/v) was obtained in 120 h with a decrease in HCN level to 4.0 μg/ml. In a two‐stage fermentation, in which the raw whey was pre‐hydrolysed and under the same fermentation conditions, the unsterilized hydrolysate yielded alcohol content of 5.5% (v/v), while the sterilized hydrolysate gave higher alcohol yield, 7.5% (v/v), in 48 h. No HCN was detected in the fermented liquour at the end of the two‐stage process.
Acid‐base solar biobattery exploiting water plants
Authors: Nešspůrková L. , Rybová R. , Janáčcek K. 
Published: December 2004

AbstractA biobattery of a new type in which pH difference between two media serves as a source of free energy is described. The ability of some algae and other water plants to change markedly the pH of their surroundings according to the light conditions can be used to maintain two solutions at widely differing pH values. Electrical energy may be obtained from this source as a by‐product to biomass production.
Growth kinetics of top and bottom cultures of Saccharomyces spp. in a chemostat using sugarbeet molasses
Authors: Alexander D. B. , Zajic J. E. , Jones L. P. 
Published: December 2004

AbstractGrowth kinetics were evaluated for three yeast strains of the genus Saccharomyces. Two topfloating strains, SF 115 and SF 116 and one flocculant yeast SF 104 were analyzed in pure and mixed cultures in 1‐liter continuous fermentation experiments in a chemostat. Growth was monitored for 72 h at 30°C in a medium containing sugarbeet molasses and 1.0 g/liter each of NH4H2PO4 and urea. SF 115 and SF 116 were found to have lower μmax values of 0.290 and 0.296 h−1, respectively, than SF 104, which had a μmax of 0.364 h−1. The two top‐floating yeasts (SF 115 and SF 116) demonstrated greater affinity for the substrate and utilized substrates at a greater rate. They have K8 values of 4.03 × 10−3 M and 3.798 × 10−3 M, respectively, compared to 9.06 × 10−3 M for SF 104. A mixed culture of SF 116 and SF and SF 104 was found to have a μmax of 0.426 h−1 with a Ks of 6.924 × 10−3 M. SF 115 grown in mixed culture with SF 104 exhibited a μmax of 0.473 h−1 with a Ks of 7.975 × 10−3 M. In both cases, the SF 104 was the dominant microbe in mixed culture systems.
Untersuchungen zur gelpermeationschromatographischen Fraktionierung von Natrium‐Ligninsulfonat
Authors: Polter E. 
Published: December 2004

AbstractThe gelpermeation chromatography of sodium ligncsulfonates with bidistilled water as an eluent is influenced by the volume expansion of the polyelectrolyte, by the negative changes of the gels, and by the inclusion effect so markedly that true conclusions on the molecular weight distribution of sodium lignosulfonate cannot be drawn. Using electrolytes as an eluent these irregularities can be avoided. Polydispersity of these macromolecules however prevents separation into discrete peaks. As a result of this behaviour changes of molecular weight distribution are only poorly recognized. Therefore, on studying biotransformation of lignosulfonic acids we purpose to use gels by which one part of the lignosulfonates is excluded, and biotransformation may be controlled by the ratio of excluded part of the lignosulfonates to that part retarded by the gels.
Simultaneous utilization of methanol and glucose by Hansenula polymorpha (Torulopsis sp.) MH 26, a chemostatic investigation on the distribution of 14C‐methanol
Authors: Müler R. H. , Babel W. , Uhlenhut G. J. 
Published: December 2004

AbstractSimultaneous utilization of methanol and glucose by Hansenula polymorpha (Torulopsis sp.) MH 26 results in an increase in growth yield of up to 18% in dependence of the mixing proportion. The distribution of carbon from 14C‐methanol into biomass and carbon dioxide was investigated. The distribution pattern was strongly influenced by the mixing proportion showing that methanol plays an increasing role as an energy donor as the glucose content in the mixture increased. Due to these data and verified by theoretical considerations the effect on growth yield was discussed to be caused by an interconnection in the conversion of the individual substrates. This is attributed to glucose delivering the acceptor for C1‐assimilation and resulting in a more efficient utilization of glucose carbon on the one as well as the energy content of methanol on the other hand.