Molecular genetic characteristics of Saccharomyces cerevisiae distillers' yeasts.

Genomes of 36 Saccharomyces distillers' strains, mainly of domestic origin, were studied by PCR-RFLP analysis of rDNA 5.8S-ITS fragment, molecular karyotyping, and Southern hybridization. Molecular analysis revealed that all the strains belonged to the species S. cerevisiae. According to the karyotypic analysis, many of the strains were aneuploid. Accumulation of polymeric genes SUC and MAL was detected in S. cerevisiae distillers' strains. Accumulation of polymeric genes of sugar fermentation may be of adaptive importance and may result in increased fermentation activity of the strains. It was demonstrated that most strains fermenting maltose after one day of fermentation possessed several MAL genes. Thermotolerant strains with high fermentation activity were selected. [ABSTRACT FROM AUTHOR]