Effect of pH stress on lipid composition of Saccharomyces cerevisiae.

Total lipids (% dry weight basis) of S. cerevisiae increased when pH of the growth medium was altered. Phospholipid content increased when the yeast was grown at a pH higher than its optimal (pH 6). Sterol content was not affected much. Sterol:phospholipid ratio was not affected by pH of the medium. Phosphatidylcholine content of S. cerevisiae was inversely related to pH of its growth medium. Glycolipids were more when the yeast was grown at pH 9. Fatty acids of S. cerevisiae grown at pH 3 were more saturated which makes the membranes less fluid.