Osmotolerant yeasts isolated from Tokaj wines.

ABSTRACT

Yeasts growing in "Tokaj Aszu" wine and in "Aszu essence" were isolated and characterised. They proved to be physiological races of Saccharomyces cerevisiae and showed high osmotolerance, which was an inherited feature rather than the result of adaptation. No correlations were found between the osmotolerance and the ethanol tolerance or the cell size and morphology. Yeasts in "Aszu essence" are usually undesirable contaminants that impair the quality of the essence. The isolate characterized in this work exhibited physiological parameters very similar to those of the "Tokaj Aszu" strain, which make it a potent competitor of other yeasts in Aszu fermentation. However, the high termo sensitivity of its cells offers a possibility to eliminate them selectively.