| Abstract
| - Yeast autolysis affects membrane stability and induces a release of vacuolar enzymes into the cellcytoplasm. Consecutively, it was important to study the evolution of sterol content in Saccharomycescerevisiae for a fourteen day period of accelerated autolysis. Unesterified and esterified sterols wereanalyzed both in the biomass and in the autolysis medium. Ten sterols were identified by gaschromatography/mass spectrometry. A second group of six sterols was separated and partiallycharacterized. Among the first group of 10 sterols, a dehydroergosterol was identified as ergosta-5,7,9(11),22-tetraen-3β-ol, not yet charaterized in S. cerevisiae. Yeast autolysis induced a decreaseof esterified sterol content, especially first intermediates in the sequence of the ergosterolbiosynthesis, as zymosterol. In contrast, the yeast autolysis resulted in the release of a low quantityof sterols into the medium. At the end of the fourteenth day of autolysis, 0.015% of the total sterolcontent of the initial biomass was found in the medium. Keywords: Yeast; autolysis; sterol; dehydroergosterol; gas chromatography/mass spectrometry;trimethylsilyl ether
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