Characterization of phytase produced by Aspergillus niger.

The extracellular activity of Aspergillus niger phytase at the end of the growth phase was 132 nkat/mL in a laboratory bioreactor. The purified enzyme has molar mass approximately 100 kDa, pH optimum at 5.0, temperature optimum at 55 degrees C and high pH and temperature stability.

Phytase from Aspergillus niger.

132 microorganisms, isolates from soil and decayed fruits, were tested for phytase production. All isolates intensively producing active extracellular phytase were of fungal origin. The most active fungal isolates with phytase activity were identified as Aspergillus niger.

Effect of increasing methanol concentrations on physiology and cytology of Candida boidinii.

Concentration of methanol in the medium strongly affected not only the physiology but also the cytology of Candida boidinii strain 2 cells in a methanol-limited chemostat at a constant dilution rate D 0.1/h and at low pH 3.0.

Characterization of catalase-negative mutants of methylotrophic yeast Hansenula polymorpha.

Three recently isolated catalase-negative mutants of Hansenula polymorpha lost the ability to grow on methanol but grew in media containing glucose, ethanol or glycerol. Their incubation in a medium with methanol resulted in an accumulation of hydrogen peroxide and cell death. During growth of a catalase-negative mutant in chemostat on a mixture of methanol and glucose, neither H2O2 accumulation nor cell death were observed up to the molar ratio of 10:1 of the two substrates.

Alcohol oxidase of methylotrophic thermo- and acidotolerant yeast Hansenula sp.

Electrophoretic analysis of alcohol oxidase purified from the methylotrophic thermo- and acidotolerant yeast Hansenula sp. revealed the presence of two active forms of the enzyme with molar mass 440 kg/mol (major component) and 724 kg/mol (minor component). A subunit M of the enzyme was found to be 72 kg/mol.

Anaerobic degradation of cellulose and formation of methane.

The existing knowledge of anaerobic digestion of cellulose-containing wastes and methane formation is reviewed. Mutual relationships between the individual phases of this complex process and the mechanism of methane biosynthesis are discussed in three sections: (1) Non-methanogenic phase and digestion of cellulose; (2) methanogenic phase and methanogenesis; (3) mixed cultures and their advantages.

Influence of pH on the formation and location of beta-glucosidase in Aspergillus terreus grown on ceLlulose.

Wild strain of Aspergillus terreus is very good producer of beta-glucosidase. It produces 15 nkat/mL (0.9 IU/mL) of extraceLlular beta-glucosidase at pH 5.

Kinetics of cellulase production in Trichoderma viride on microcrystalline cellulose.

During the cultivation of a wild strain of T. viride on microcrystalline cellulose the synthesis of cell-bound FP cellulases precedes cell growth. During the growth they are released into the medium as extracellular enzymes.

Cell growth and cellulase production in Trichoderma viride on microcrystalline cellulose.

The production of CM and FP cellulases was studied during the growth of a wild strain of Trichoderma viride on microcrystalline cellulose. Part of the enzymes was found to be released into the medium while another part remained bound to the cell. Bound cellulases are released into the medium at the stage of cell lysis which takes place in the post-stationary phase.

Growth of Candida tropicalis 2838 cells on straw hydrolyzates.

Improved strain of Candida tropicalis 2838 grows on nonseparated straw hydrolyzates with no addition of vitamins and trace elements at a specific growth rate mu = 0.34 and 44% yield coefficient (referred to reducing substances). The reducing substances in hydrolyzates contain predominantly monosaccharides (xylose, glucose, arabinose, mannose).

Selection of a yeast strain with optimal utilization of straw hydrolyzates.

The dry nonseparated straw hydrolyzates prepared by mild acid hydrolysis of milled straw contains 25--30% of reducing substances, mostly saccharides with prevalence of xylose. A strain utilizing the neutralized nonseparated hydrolyzates without any growth substances added was obtained by selection and long-term adaptation of an array of yeast strains. The strain, identified as Candida tropicalis 2838, exhibited high cell-growth rate and considerable yield of protein-rich biomass.

[Yeast growth on solid natural oil].

Two strains of the yeast Candida lipolytica with a specific response to n-alkanes could grow on a medium with paraffins only in the case of contact of the cells with the particles of hydrocarbons. A mixture of paraffins with a solidification point of 35 degrees C contained 41.6% of n-alkanes with the carbon chain from C8 to C36.

Studies on methanol - oxidizing yeast. III. Enzyme.

Oxidation of methanol, formaldehyde and formic acid was studied in cells and cell-free extract of the yeast Candida boidinii No. 11Bh. Methanol oxidase, an enzyme oxidizing methanol to formaldehyde, was formed inducibly after the addition of methanol to yeast cells.