INTERACTION BETWEEN ISOLATION SOURCE, CELLULAR FATTY-ACID COMPOSITION AND STRESS TOLERANCE IN SACCHAROMYCES-CEREVISIAE AND ITS SUBSPECIES

The physiological properties and fatty acid content of 59 strains of Saccharomyces cerevisiae isolated from soft-drink factories, a fruit puree factory, a fuel-alcohol distillery and a winery were compared. Discriminant analysis of the results allocated the strains to four groups according to their source. Resistance to preservatives and temperature stress were correlated with differences in fatty acid composition. The fatty acid C18 : 1 Delta 11, growth at pH 2 and in the presence of 200-600 mg l(-1) benzoate or sorbate, and maximal growth rate at 42 degrees C were characteristics associated with yeasts from particular environments. However, tolerance of thermal stress and content of the C18 : 2 fatty acid were associated with subspecies: the former species S. capensis, S. chevalieri, etc. The relative content of C10 : 0, C12 : 0 and C18 : O acids varied according to both isolation source and subspecies.