bluuebunny/crossref_metadata_2025_split huggingface dataset:
Production of oxytetracycline by immobilized Streptomyces rimosus cells in calcium alginate gels
Authors: Farid M. A. , El Diwany A. I. , El Enshasy H. A. 
Published: December 2004

AbstractStreptomyces rimosus Pfizer 18234–2 cells were immobilized in calcium alginate and used for the production of oxytetracycline. The influence of the incubation period, alginate concentration and storage in CaCl2 were investigated. From the results of the repeated batch fermentations of the shake flasks, a good level of antibiotic was maintained for a period of about 28 days using 4% calcium alginate. The cell leakage and cell concentration inside the beads were affected by the alginate concentration and storage in CaCl2 solution.
Stimulation of multiple shoot regeneration from seedling leaves of Hypericum perforatum L. by pluronic F‐68
Authors: Brutovská R. , Cellárová E. , Davey M. R. , Power J. B. , Lowe K. C. 
Published: December 2004

AbstractThe effects of the non‐ionic surfactant, Pluronic F‐68, on the growth of shoots regenerated from seedlings (14 days post‐germination) of Hypericum perforatum L. were studied. The supplementation of agar‐solidified medium with 0.001% (w/v) of Pluronic increased the mean fresh weight of the regenerants after 60 days by 40% and the mean number of plant regenerants recovered per seedling by 34%; a less pronounced increase in the number of regenerants occurred with 0.01% (w/v) of the surfactant. By contrast, the mean fresh weight of the regenerants cultured in the presence of 0.1% (w/v) Pluronic F‐68 was 15% lower than untreated controls, although the mean number of regenerants per seedling remained unaltered. The growth of seedling leaf‐derived Hypericum callus after 60 days was unaffected by all the concentrations of Pluronic tested. However, there was a tendency for callus cells grown in the presence of Pluronic to be more highly pigmented with anthocyanins. The cultivation of leaf explants with 0.001% or 0.01% (w/v) Pluronic did not affect either the mean fresh weight of the regenerants or the mean number of regenerants per explant. However, decreases in both the mean fresh weight and the mean number of regenerants (both 33.0% lower than the control) occurred following the cultivation with 0.1% (w/v) Pluronic.
Glucose oxidase biosynthesis in relation to biochemical mutations in Aspergillus niger
Authors: Fiedurek J. , Szczodrak J. 
Published: December 2004

AbstractThe production of extracellular glucose oxidase in a submerged culture by a number of auxotrophic, 2‐deoxy‐D‐glucose resistant and protease‐less mutants of Aspergillus niger was evaluated. Among the auxotrophic strains, no evident dependence was found between the kind of the nutritional requirements and the level of the glucose oxidase activity. However, the majority of auxotrophs, requiring serine or niacin, showed a higher enzyme activity (from 16 to 680%) than the parent strain. The dynamics of the glucose oxidase synthesis by the free and immobilized mycelium of the most active niacin− mutant of A. niger was also investigated.
Changes in protein secretion of Aspergillus niger caused by the reduction of the water activity by potassium chloride
Authors: Bobowicz‐Lassociska T. , Grajek W. 
Published: December 2004

AbstractThe effect of the rapid reduction of the water activity (aw) on the extracellular protein and amylolytic activity of Aspergillus niger was studied. An aw value gradient from 0.90 to 0.99 in KCl solutions was applied for the mycelium treatment. It was found that the aw reduction considerably influenced the protein secretion. This phenomenon was dependent on the age of the treated mycelium and the range of the aw gradient. The highest protein and enzyme secretion yields were obtained at aw = 0.98 using a 72‐h old mycelium. In comparison with the non‐treated mycelium, the increase in the secretion amounted to about 60% for the amylolytic activity and 37% for the soluble protein, respectively. It was shown that the mycelium incubated in KCl solutions of an aw value from 0.90 to 0.99 had the ability for regeneration in fresh CZAPEK‐DOX medium. The effect of the osmotic shock on the protein secretion was limited only for the treated cell population and declined in the mycelium which was regenerated after the transfer into the culture medium.
Non‐selective precultivation of bacteria able to degrade different polycyclic aromatic hydrocarbons (PAH)
Authors: Mahro B. , Rode K. , Kasche V. 
Published: December 2004

AbstractThe influence of the precultivation with different carbon sources on the ability of three different bacterial strains (Sphingomonas sp. strain BA2, Gordona sp. strain BP9, Mycobacterium sp. strain VF1) to grow on phenanthrene. anthracene, pyrene or fluoranthene as the sole source of carbon and energy were studied. The strains were found to maintain their ability to grow on two of the four PAH after 30 serial transfers in liquid nutrient broth medium without selective pressure. The ability to grow on these PAH as the sole carbon and energy source was also maintained after curing experiments with acridine orange. The high stability of the PAH‐degradation phenotype suggests that the tested strains carry at least parts of the PAH‐degradation pathway genes on the chromosome. The PAH‐degradation versatility of the strains was also influenced by the carbon source being used for precultivation. Possible reasons for the particularly good impact of the precultivation on hexadecane on the PAH degradation are discussed in this paper.
Improved ethanol production from whey with Saccharomyces cerevisiae using permeabilized cells of Kluyveromyces marxianus
Authors: Rosenberg M. , Tomáška M. , Kaňuch J. , Šurdík E. 
Published: December 2004

AbstractPermeabilized cells of Kluyveromyces marxianus CCY eSY2 were tested as the source of lactase in the ethanol fermentation of concentrated deproteinized whey (65–70 g/l lactose) by Saccharomyces cerevisiae CCY 10–13–14. Rapid lactose hydrolysis by small amounts of permeabilized cells following the fermentation of released glucose and galactose by S. cerevisiae resulted in a twofold enhancement of the overall volumetric productivity (1.03 g/l × h), compared to the fermentation in which the lactose was directly fermented by K. marxianus.
Enhancement of the biological degradation of soils contaminated with oil by the addition of compost
Authors: Hupe K. , Lüth J.‐C. , Heerenklage J. , Stegmann R. 
Published: December 2004

AbstractThe fundamentals of the biological treatment of contaminated soils were investigated in bioreactors with the aim to optimize the processes of biological soil treatment in order to achieve the highest possible degree of degradation within the shortest period of time. Preinvestigations using test systems at different scales have provided information about the possibilities of enhancing the decomposition processes which are dependent on various factors, such as milieu conditions, additives, etc., that must be known before remedial actions are taken.The investigations made so far have shown that compost is a favourable additive when oil‐contaminated soils are biologically treated. The degradation of contaminants can be enhanced by the addition of compost. This positive effect is attributed to various mechanisms. In this paper, results of a variety of test systems at different scales are presented.In test series, different amounts of biocompost were added to investigate the influence on the degradation of diesel fuel. It was demonstrated that by increasing the compost content – the cumulative O2 consumption caused by the degradation of the diesel fuel contaminants increased.It could be shown that the reduction of the diesel fuel contaminants in the soil was independent of the compost age and amounted to approximately 94% of the initial quantity.The addition of biocompost could also enhance the degradation of real contaminants. After a test period of 162 days in set‐ups with compost addition, more than 75% of the lubricating oil contaminants disappeared, while less than 37% of the contaminants disappeared in set‐ups without compost addition.Moreover, by the addition of compost, the formation of pellets during the dynamic treatment of soil materials could be reduced.
Performance of industrial scale bioreactors with modified RUSHTON turbine agitators
Authors: Roman R. V. , Tudose Z. R. , Gavrilescu M. , Cojocaru M. , Luca S. 
Published: December 2004

AbstractThe data presented here with respect to the behaviour of industrial scale stirred tank bioreactors equipped with modified RUSHTON turbine agitators in the biosynthesis processes of antibiotics are valid for that case that the power consumption is the same as it is in standard RUSHTON turbine agitators.Each modified RUSHTON turbine agitator was obtained through the variation of the blade surface by adding perforations so that the ratio between the perforation surface area and the full surface area (or the surface fraction of the perforations) is 0.36.In the fermentations of Streptomyces aureofaciens, Streptomyces rimosus and Penicillium chrysogenum producing tetracycline, oxytetracyline and penicillin, respectively, in bioreactors equipped with modified RUSHTON turbine agitators, the relative antibiotic production is increased by more than 30% compared to standard bioreactors.
Isolation and characterization of an alkaliphilic bacterium capable of growing on 2,4‐dichlorophenoxyacetic acid and 4‐chloro‐2‐methylphenoxyacetic acid
Authors: Hoffmann D. , Müller R. H. , Kiesel B. , Babel W. 
Published: December 2004

AbstractA bacterial strain, called P4a, was isolated from debris of concrete samples of a demolished herbicide factory. The samples were contaminated with chlorinated and methylated phenoxyalkanoic acids. Strain P4a was able to utilize 2,4‐dichloro‐ (2,4‐D) and 4‐chloro‐2‐methylphenoxyacetic acid (MCPA) as the sole source of carbon and energy; degradation of 2,4‐dichlorinated and 4‐chloro‐2‐methylated phenoxypropionic acid and ‐butyric acid derivatives was not found. Growth on 2,4‐D was observed from a pH of 5.6 up to a pH of about 10, with optimum growth at around 8.5. No supplements were found to be required for growth on 2,4‐D, but the presence of yeast extract increased the growth rate from less than 0.05 h−1 to 0.2 h−1. The strain was metabolically active up to pH values of 12, which corresponded to the pH of aqueous eluates from such material. It was able to degrade 2,4‐D under these conditions up to an initial concentration of 400 mg/1 and in fact did degrade 1,600 mg/l of 2,4‐D at an initial pH value of 11. Strain P4a was tentatively identified as Comamonas acidovorans on the basis of the substrate utilization pattern (BIOLOG), fatty acid profile (MIS) and G+C content.
Selection of hemicellulosic hydrolysate pretreatments and fermentation conditions to stimulate xylitol production by ethanol‐producing yeasts
Authors: Converti A. , Del Borghi M. 
Published: December 2004

AbstractXylitol production from hardwood hemicellulosic hydrolysates by well‐known ethanol‐producing yeasts was stimulated through an experimental schedule including pretreatments of the hydrolysate, the choice of the best xylitol producer and the selection of the optimum fermentation conditions. The xylitol or ethanol yields obtained on consumed xylose demonstrated that their production was stimulated under completely different conditions, as to be expected by the fact that these catabolites are the final products of different metabolic pathways. In particular, the catabolism of Pachysolen tannophilus, that is the best ethanol producer from this natural substrate, could be targeted towards xylitol rather than towards ethanol production by ensuring a strongly reducing environment through a suitable pretreatment of the hydrolysate. The final removal of fermentation inhibitors by adsorption onto highly adsorbing substances allowed a further 20% xylitol yield increase.
Mixing times in an external‐loop airlift bioreactor with static mixers
Authors: Gavrilescu M. , Roman R.‐V. 
Published: December 2004

AbstractThe influence of static mixers on mixing time and circulation time in an external‐loop airlift bioreactor with gas‐induced and forced‐liquid circulation was investigated.The study was carried out with water and three viscous, non‐Newtonian starch solutions. The mixing time was determined for the overrall flow loop using a classical tracer response technique.It was found that the mixing time is highly dependent on the superficial gas velocity and the presence of static mixers. The shortest mixing time is achieved in a forced‐loop airlift reactor without static mixers, where the average mixing time value is only 1/3 of the time necessary for mixing in the airlift reactor with gas‐induced liquid circulation and static mixers.The pseudoplasticity of the liquid phase insignificantly influences the mixing time and the circulation time.
Hydrolyzed whey as a medium for propionic acid fermentation
Authors: Czaczyk K. , Trojanowska K. , Wiszumirska E. 
Published: December 2004

AbstractWhey, hydrolyzed by using pure enzymes and enzymatic preparations, was fermented by propionic acid bacteria in batch cultures. The course of propionic acid fermentation was examined by the determination of cell dry weight, lactose utilization, production of volatile free acids and biosynthesis of vitamin B12. The production of propionic acid by Propionibacteria increased when hydrolyzed whey was used as a medium. It rose from 6.3 to 6.7 g/l in the control compared to 8.0–8.8 g/l when pepsin, papain, alcalase, or pescalase were applied as hydrolyzing agents. A significant decrease in the biosynthesis of vitamin B12 (more than 50%) was observed in all cases compared to the control (cultivation on medium without hydrolysis).
Flow cytometric discrimination between Acinetobacter calcoaceticus 69‐V and Alcaligenes eutrophus JMP134 by fluorescently labelled rRNA‐targeted oligonucleotide probes and DNA staining
Authors: Herrmann C. , Babel W. Th. , Lösche A. , Müller S. , Bley S. 
Published: December 2004

AbstractIn situ hybridization with fluorescently monolabelled rRNA‐targeted oligonucleotide probes (17 to 18 nucleotides) was used to discriminate between Alcaligenes eutrophus JMP 134 and Acinetobacter calcoaceticus 69‐V by flow cytometry. The strains were grown in batch experiments in a mixed population. The forward light scatter and fluorescence of each bacterial cell were measured with a single laser cytometer. The intensity of fluorescence after rRNA staining depended on the content of ribosomes, which correlated with the growth rate of bacteria. Therefore exponentially growing cells could be clearly detected. For other growth phases, signal amplification was necessary using multiple probes. The two bacterial strains were identified with differently labelled probes under an epifluorescent microscope. Using a single laser cytometer, rRNA based identification was possible nut not ideal. Better discrimination between the two strains of the mixed population was achieved by DNA staining, combined with the different forward light scatter signals. Due to the significantly different cellular DNA and GC content of both strains, the fluorescent dye DAPI (4′, 6‐diamidino‐2‐phenylindole), preferring AT‐rich regions of DNA, was found to be a supplementary tool for population analysis. The abundance ratios of the two strains in mixed culture determined by DNA or rRNA staining were similar.
Studies on cultivation, biological efficiency and chemical analysis of Pleurotus sajor‐caju (FR.) SINGER on different bio‐wastes
Authors: Patrabansh S. , Madan M. 
Published: December 2004

AbstractThree different kinds of biomass, namely Populus deltoides, Eupatorium adenophorum and sericulture waste were used individually for the cultivation of Pleurotus sajor‐caju, alone and mixed with paddy straw. P. sajor‐caju, when used alone, exhibited a very good colonizing ability on these substrates, except in sericulture waste. The biological efficiency of P. deltoides and E. adenophorum when used as pure substrate was 75 and 77%, respectively, but it increased to 102% when P. sajor‐caju was cultivated in a mixture with paddy straw in a ratio of 1:2. Experiments examining the growth on sericulture waste in both pure and mixed substrate are encouraging. From the analysis of substrate before and after the cultivation of P. sajor‐caju it was noted that subsstrates were enriched in their protein content as a result of growth of this mushroom. The percentage of degradation of cellulose, hemicellulose and lignin showed that P. sajor‐caju is capable of utilizing all three major components. The fruit bodies of P. sajor‐caju were analyzed for crude protein content, crude fat and carbohydrate content. The energy values in the fruit bodies of P. sajor‐caju and different organic wastes were found to vary from 282 to 309 kcal/100 g and from 319 to 467 kcal/100 g, respectively. It was found, however, that the energy recovery from organic wastes by fruit bodies was very low, i.e. 4.19‐8.73 kcal/100g of dry substrate.
Hydrolysis and transformation of cellulose with Aspergillus niger IBT‐90 enzymes
Authors: Galas E. , Pyc R. , Romanowska I. 
Published: December 2004

AbstractHydrolysis and transformation of Fibrenier cellulose (USA) with enzymes from Aspergillus niger IBT‐90 was studied. The process was performed at 50°C and pH 4.8 for 24 h using an enzyme complex either as a properly diluted culture filtrate or as a mixture of isolated and purified enzymes from A.niger IBT‐90. In the latter experiments, enzyme‐substrate ratios expressed as units of activity per 1 g of cellulose were as follows: endoglucanase E1 and E2, 40; β‐glucosidase, 40 and cellobio‐hydrolase, 2. Cellulose concentration was 5%. It was proved that the crude celluloytic complex from A. niger IBT‐90 exhibits higher efficiency in the decomposition of cellulose in comparison to the mixture of enzymes isolated from this complex, as was revealed in assays of reducing sugars and determinations of light transmission throughout cellulose fibres using a computer analysis of the microscopic image. Comparison of both the endoglucanases E1 and E2 showed that the first enzyme is more active against cellulose. It liberated more reducing sugars and caused more significant decomposition of fibres. The predominant effect of the endoglucanase E2 was a smoothing of the fibre surface. The cellobiohydrolase split a cellulose fibre into many short fibres.
β‐Galactosidase in immobilized cells of Daucus carota L.
Authors: Poór J. 
Published: December 2004

AbstractThe cell suspension culture Daucus carota L. was permeabilized by Tween 80 and immobilized by glutaraldehyde. β‐Galactosidase showed an optimum pH of 4.7 and an optimum temperature of 55 °C. The enzyme hydrolysis was linear for 3 h, reaching a 65% conversion. A very good level of storage stability was achieved when using dry catalyst, or a solution of 0.15 M NaCl with the addition of chloramphenicol, (l‐methyldodecyl)‐dimethylamin‐4‐oxide (ATDNO), chlortetracycline hydrochloride (CLCTC) or by freezing the immobilized cells in 0.15 M NaCl. The cells characterized by high enzyme activity and stability in long‐term storage showed convenient physicomechanical properties.
Development of toxicity tolerant water hyacinth (Eichhornea crassipes) for effective treatment of raw sewage
Authors: Ayade B. B. 
Published: December 2004

AbstractPioneering research efforts in the handling of municipal sewage in developing countries have involved the use of water hyacinth (Eichhornea crassipes) to purify sewage for possible re‐use of the effluent water for domestic purposes. The ability of water hyacinth to remove pollution from raw sewage has been found to be impaired by sewage toxicity. Trials were therefore carried out to adapt water hyacinth to toxicity and thereby increase its ability to remove pollutants from raw sewage. The plants were adapted using an active bio‐degrader consisting of Pseudomonas aeruginosa, Escherichia coli, Klebsiella ozaenae, Klebsiella edwardsiella and Baccillus subtilis. The adaptation progressed through 20, 40, 60 and 80% sewage dilution until plants capable of growth in 100% raw sewage were obtained. Plants were observed for morphological growth and at four weeks, samples were collected for tissue analysis.The plants progressively absorbed nutrients from sewage up to the fourth week, when signs of toxicity were obsereved through wilting, loss of turgidity and reduction in leaf number. However, plants that survived through a series of adaptations under various sewage dilutions exhibited luxuriant growth on raw sewage. In synergy with the active bio‐degrader, the efficiency of the adapted water hyacinth to remove pollutants (nutrients) from raw sewage was enhanced by 93%.
Characteristics of immobilized thermostable amylases from two Bacillus licheniformis strains
Authors: Ivanova V. , Dobreva E. , Legoy M. D. 
Published: December 2004

AbstractCovalent immobilization of thermostable α‐amylases from catabolite resistant and sensitive Bacillus licheniformis strains on controlled pore glass (CPG) and porous silica (Spherosil) beads and ionic binding on DEAE‐cellulose, Amberlite and Dowex were investigated. Preparations with satisfactory operational stabilities and activities up to 1,600 U/g of support (ionic binding) and 800 U/g carrier (covalent coupling) were obtained. Immobilization led to a narrowing of the pH interval of maximum activity. The fixed amylases were stable in limited pH regions around the optimum pH level. An enhancement of the enzyme thermostability was observed. Apparent shifts of the optimum temperatures were not found. The apparent Vmax decreased up to 80 times. The Km′ remained unchanged (for amylopectin as the substrate) or increased up to 10 times (soluble starch). Maltose, maltotriose and maltopentaose were the main products of the hydrolysis. A significant increase in maltopentaose content was observed.
Growth of Thermus aquaticus and its TaqI endonuclease production
Authors: Altintas M. M. , Ülgen K. Ö. 
Published: December 2004

AbstractThe culture behaviour of Thermus aquaticus was characterized. The response of the bacterium to various carbon (tryptone, glucose, glycerol) and nitrogen sources (yeast extract, NaNO3, (NH4)2SO4, leucine, thymine, thiamine, glutamic acid) was studied. Amino acids did not support growth, but CASTENHOLZ salt medium supplemented with yeast extract and glucose or tryptone resulted in good growth and production. A suitable medium composition giving the highest biomass concentration and enzyme yield was developed. The simple medium containing TYE‐NaCl resulted in the highest biomass concentration, whereas CASTENHOLZ mineral medium supplemented with tryptone and yeast extract gave the highest specific activity and enzyme yield. The effect of inoculum age and size on growth was also investigated in order to improve the yield and process consistency. The use of shake flasks inoculated with precultures at their early or late stationary phase resulted in the same biomass concentration (0.56 ± 0.015 g/l) and similar maximum specific growth rates (0.258 ± 0.003 h−1). Inoculum sizes between 1 and 2.5 per cent were optimal for cell growth. As the other papers on thermophilic microorganisms, including the T. aquaticus YT‐1 strain, gave qualitative information on growth, the results presented here cannot be compared with others on a quantitative basis. TaqI endonuclease was purified using a 5 step protocol including cell disruption, adsorption, precipitation, column chromatography and final dialysis. The enriched fraction had a specific activity of 33,600 U TaqI endonuclease per mg protein.