Transformation of cellobiose during the interaction of cellobiose dehydrogenase and β-glucosidase of Cerrena unicolor.

This work investigated the regulatory role of the interaction between cellobiose dehydrogenase (CDH) and β-glucosidase (β-GLU) in the conversion of cellobiose into cellobionolactone or glucose in vitro. To study the regulation, the two enzymes were isolated from the culture medium of the fungus Cerrena unicolor grown on a medium with microcrystalline cellulose. The enzymes were obtained in an electrophoretically homogeneous state.

[Morphological, Physiological, and Biochemical Characteristics of a Benzoate-Degrading Strain Rhodococcus opacus 1CP under Stress Conditions].

Ability of actinobacteria Rhodococcus opacus 1CP to survive under unfavorable conditions and retain its biodegradation activity was assessed. The morphological and ultrastructural features of R. opacus 1CP cells degrading benzoate in the presence of oxidants and stress-protecting agents were investigated.

[Xylanase and cellulase of fungus Cerrena unicolor VKM F-3196: production, properties, and applications for the saccharification of plant material].

Under the conditions of submerged cultivation in a medium containing microcrystalline cellulose, the Cerrena unicolor VKM F-3196 basidiomycete is capable of producing xylanase and cellulase. Electrophoretically homogeneous cellulase and xylanase were obtained using ion exchange and hydrophobic chromatography. The molecular weight of both cellulase and xylanase was -44 kDa.

[Immobilization of a recombinant strain producing glucose isomerase on SiO2-xerogel and properties of prepared biocatalysts].

An original method of immobilization of nongrowing microorganism cells on xerogel of silicon dioxide containing insoluble hydroxyl compounds of cobalt(III) has been developed. A recombinant strain producing glucose isomerase has been constructed on the basis of Escherichia coli with the use of a gene of Arthrobacter nicotianae. It was revealed that glucose isomerase activity and stability of biocatalysts prepared on the basis of the recombinant E.

[Xylose isomerase constitutive biosynthesis in Arthrobacter nicotianae].

The specific features of biosynthesis of the cell-bound xylose isomerase by the actinobacterium Arthrobacter nicotianae BIM V-5 were studied. It was demonstrated that the constitutive synthesis of this enzyme in the studied bacteria, not subject to catabolite repression, was inhibited by xylulose, an intermediate product ofxylose utilization and the final product of its enzymatic isomerization. Short-term experiments demonstrated that xylulose at a concentration of 0.

[Catalytical properties of Arthrobacter nicotianae cells, a producer of glucose isomerase, immobilized in xerogel of silicium dioxide].

Arthrobacter nicotinanae cells, producers of glucose isomerase, were immobilized in xerogel of silicium dioxide, and properties of the resulted heterogeneous biocatalysts were investigated in the process of isomerization of monosaccharide (glucose and fructose). The glucose isomerase activity of the resulted biocatalysts was shown to be 10 U/g, on average, taking into account the loss of the activity upon the immobilization, which amounted to 50% of the cell activity in suspension. The rate of the fructose isomerization increased linearly in the range of 55-80 degrees C with the temperature coefficient 1.

[Catabolite repression of xylose isomerase synthesis in Arthrobacter ureafaciens].

The effect of a specific substrate as well as other carbon sources on the biosynthesis of xylose isomerase in the actinobacterium Arthrobacter ureafaciens BIM B-6 has been studied. It was established that xylose and its structural analogue xylite induced the production of the enzyme by bacterial cells. The inducing effect peaked at a concentration of specific substrates of 0.

[Glucose isomerase activity in suspension of Arthrobacter nicotianae cells and adsorption immobilization of the microorganisms on inorganic carriers].

Kinetics of monosaccharide isomerization has been studied in suspensions of intact, non-growing Arthrobacter nicotianae cells. Under the conditions of the study, glucose and fructose were isomerized at the same maximum rate of 700 micromol/min per 1 g dried cells, which increased with temperature (the dependence was linear at 60-80 degrees C). The proposed means of adsorption immobilization of A.

[Spontaneous variability of glucose oxidase-producing fungus Penicillium adametzii LF F-2044].

The glucose oxidase-producing fungus Penicillium adametzii LF F-2044 was studied for natural variability. Four variants of the fungus differed in morphological characteristics and glucose oxidase synthesis. The synthesis of extracellular glucose oxidase and the productivity of morphological variants P.

[Biosynthetic features and properties of xylose isomerases from Arthrobacter nicotianae, Escherichia coli, and Erwinia carotovota subsp. atroseptica].

The characteristics of xylose isomerase biosynthesis in the bacteria Arthrobacter nicotianae BIM B-5, Erwinia carotovota subsp atroseptica jn42xylA, and Escherichia coli HB101xylA have been studied. The bacteria formed the enzyme constitutively. Out of the carbon sources studied, D-glucose and D-xylose were most favorable for the biosynthesis of xylose isomerase in E.

[Growth characteristics and glucose oxidase production by mutant Penicillium funiculosum strains].

The main parameters of growth and glucose oxidase production by the mutant Penicillium funiculosum strains BIM F-15.3, NMM95.132, and 46.

[A plate method to screen for microorganisms producing xylose isomerase].

A plate method was developed to screen for xylose isomerase-producing microorganisms based on the use of 2,3,5-triphenyltetrazolium as an indicator of D-xylulose, the D-xylose isomerization product. The use of this method allows microorganisms to be differentiated by the character of the enzyme synthesis (inducible or constitutive).

[Xylose(glucose) isomerase reactivity of immobilized Arthrobacter sp].

The study of the xylose/glucose isomerase-containing Arthrobacter sp. B-5 cells immobilized in cobalt hydroxide gel showed that immobilization increases the substrate affinity of the enzyme, its thermo- and pH-optima of action and stability, and makes unnecessary the addition of stabilizing cobalt ions to the isomerization medium.

[Composition and biological activity of submerged mycelium of the xylotrophic basidiomycete Lentinus edodes].

The composition of submerged mycelium of Lentinus edodes, grown in laboratory fermenters, has been studied. The mycelium contained 23-24% proteins, 8-9% lipids, up to 1800 mg% phenolic substances, and a significant amount of inorganic substances, including calcium and iron. The fungus produced up to 5.

[Development of the biological preparation enatin with broad-range antimicrobial action].

Physiological and biochemical traits of epiphytic spore forming bacteria Bacillus pumilis BIM V-263 were examined. The nutrient medium and conditions for submerged cultivation of the strain were selected. The growth dynamics and antagonistic activity during cultivation in a laboratory fermenter ANKUM-2M were studied.

[Selection of Penicillium funiculosum strains with high glucose oxidase activity].

Metabolic inhibitors, riboflavin, and end products of glucose oxidation were shown to hold much promise for the selection of Penicillium funiculosum mutant strains with a high glucose oxidase activity. The incidence of positive mutations was highest in clones resistant to sodium azide, riboflavin, and beta-D-glucono-delta-lactone. Enzyme activity in Penicillium funiculosum mutants was studied under conditions of submerged cultivation.

[Thermal stability of Penicillium adametzii glucose oxidase].

The thermal stability of glucose oxidase was studied at temperatures between 50 and 70 degrees C by kinetic and spectroscopic (circular dichroism) methods. The stability of glucose oxidase was shown to depend on the medium pH, protein concentration, and the presence of protectors in the solution. At low protein concentrations (< 15 micrograms/ml) and pH > 5.

[Preparation and characteristics of mutant strains of Penicillium funiculosum--producers of glucose oxidase].

After the mutagenesis of Penicillium funiculosum with UV light and N-nitroso-N-methylurea, 83 of 2237 grown colonies were surrounded with increased zones of glucose oxidase diffusion. Analysis of the glucose oxidase activity of selected mutant strains grown in submerged cultures allowed 18 mutant strains to be obtained whose glucose oxidase activity was 5-153% higher (in a medium with glucose) and 4-83% higher (in a medium with sucrose) than that of the parent strain. Two of these mutant strains, UV6.

[Isoelectric characterization of extracellular polygalacturanases of various Aspergillus alliaceus strains].

The composition of pectin hydrolase complexes produced by various Aspergillus alliaceus strains was studied under the conditions of induction, catabolite repression, or constitutive synthesis. The strains were found similar in terms of the polygalacturonase spectrum and different with regard to the levels of endo- and exoenzyme activities. The analysis of the zymograms of inducible polygalacturonases revealed that all tested cultures contained at least 24 molecular forms of polygalacturonase.

Effect of aromatic compounds on cellular fatty acid composition of Rhodococcus opacus.

In cells of Rhodococcus opacus GM-14, GM-29, and 1CP, the contents of branched (10-methyl) fatty acids increased from 3% to 15 to 34% of the total fatty acids when the cells were grown on benzene, phenol, 4-chlorophenol, chlorobenzene, or toluene as the sole source of carbon and energy, in comparison with cells grown on fructose. In addition, the content of trans-hexadecenoic acid increased from 5% to 8 to 18% with phenol or chlorophenol as the carbon source. The 10-methyl branched fatty acid content of R.

Utilization of Halogenated Benzenes, Phenols, and Benzoates by Rhodococcus opacus GM-14.

Strain GM-14 was isolated by selective enrichment from contaminated soil with chlorobenzene as the sole source of carbon and energy. It utilizes an exceptionally wide spectrum of haloaromatic substrates. It is a gram-positive, weakly acid-fast actinomycete, with a morphological cycle from cocci and short rods to long rods and branched filaments; it grew optimally at 28(deg)C; and it tolerated 5% NaCl in rich medium.

Three polygalacturonases constitutively synthesized by Aspergillus alliaceus.

Of three molecular forms of polygalacturonases synthesized by Aspergillus alliaceus on glucose media, two were exopolygalacturonases (exoPG1 and exoPG2) and one was an endopolygalacturonase (endoPG). Low-methoxylated beet pectin was the preferred substrate for the endoPG and exoPG2 whereas pectic acid was the optimal substrate for exoPG1. The highest activities of endoPG, exoPG1 and exoPG2 were at pH 5.

Biosynthesis of pectinlyases in Penicillium adametzii, P. citrinum and P. janthinellum.

Pectinlyase complexes of Penicillium adametzii, P. citrinum and P. janthinellum occur as multiple molecular forms distinguished by their biosynthetic control.

Selection of a mutant strain of Lipomyces kononenkoae with dextranase synthesis resistant to catabolite repression.

A mutant strain of Lipomyces kononenkoae 2896-3 synthesizing dextranase but resistant to catabolite repression was obtained using N-nitroso-N-methylurea treatment. Enzyme biosynthesis in media with dextran and other carbon sources was then characterized. The capacity of the mutant to produce dextranase when grown on hydrolysed corn starch is demonstrated.