[Hybrid formation and copulation activity in the yeast Pachysolen tannophilus].

The copulation activity and hybrid formation efficiency have been studied in the xylose-assimilating yeast Pachysolen tannophilus. It was shown that the presence of 2% D-glucose, 0.5% yeast extract, and 2% agarose in the growth medium provided for the highest frequencies of hybrid formation.

[Conditions favoring differentiation and stabilization of the life cycle of the yeast Pachysolen tannophilus].

Conditions favoring differentiation and stabilization of the life cycle of the yeast Pachysolen tannophilus have been studied. When concentrations of the carbon source in the medium were lower than 100 g/l, it was found to be favorable to the mating of vegetative cells, both haploid and diploid. The addition of nitrogen and sulfur sources to the medium influenced the life phases of haploid cells and partially stabilized the vegetative growth of diploid cells.

[Activity of the key enzymes in xylose-assimilating yeasts at different rates of oxygen transfer to the fermentation medium].

The activities of xylitol dehydrogenase and xylose reductase in the yeasts Candida shehatae, C. didensiae, C. intermediae, C.

[The activity of xylose reductase and xylitol dehydrogenase in yeasts].

The activity and the cofactor specificity of xylose reductase and xylitol dehydrogenase were studied in extracts of yeasts from the genera Candida, Kluyveromyces, Pachysolen, Pichia, and Torulopsis grown under microaerobic conditions. It was found that xylitol dehydrogenase in all of the yeast species studied is specific for NAD+; xylose reductase in the xylitol-producing species C. didensiae, C.

[Specific features of fermentation of D-xylose and D-glucose by xylose-assimilating yeasts].

The ability to assimilate D-glucose and D-xylose was studied in 21 yeast species of the following genera: Candida, Kluyveromyces, Pachysolen, Pichia, and Torulopsis. All the cultures fermented D-glucose with the formation of ethanol. During the assimilation of D-xylose, ethanol was produced by P.