Characterization by gas chromatography/mass spectrometry of sterols in Saccharomyces cerevisiae during autolysis

Yeast autolysis affects membrane stability and induces a release of vacuola r enzymes into the cell cytoplasm. Consecutively, it was important to study the evolution of sterol content in Saccharomyces cerevisiae for a fourteen day period of accelerated autolysis. Unesterified and esterified sterols w ere analyzed both in the biomass and in the autolysis medium. Ten sterols w ere identified by gas chromatography/mass spectrometry. A second group of s ix sterols was separated and partially characterized. Among the first group of 10 sterols, a dehydroergosterol was identified as ergosta-5,7,9(11),22- tetraen-3 beta-ol, not yet charaterized in S. cerevisiae. Yeast autolysis i nduced a decrease of esterified sterol content, especially first intermedia tes in the sequence of the ergosterol biosynthesis, as zymosterol. In contr ast, the yeast autolysis resulted in the release of a low quantity of stero ls into the medium. At the end of the fourteenth day of autolysis, 0.015% o f the total sterol content of the initial biomass was found in the medium.