Isolation and Chemical Composition of Intracellular Oil Globules From the Yeast Lipomyces Starkeyi

An isolation method and some analytical results of intracellular oil globules of the yeast Lipomyces starkeyi are described. Protoplasts, prepared by digestion of the cells with snail gut juice, were lysed by hypotonic osmotic shock. The oil globules in the lysate were separated by repeated centrifugations and floatations through discontinuous sucrose buffer solutions.Scanning electron microscopic observations revealed the presence of membranous outer surface on the oil globules. Oil globules contained triglyceride as a major component which represented about 85% of the lipid carbon. Oil globules were found to contain polar lipids and protein as minor components. Analytical data on the polar lipids by thin-layer chromatography showed the main polar lipid to be phosphatidylethanolamine which represented over 95% of the polar lipid carbon. The presence of phosphatidylcholine, phosphatidylserine, and/or phosphatidylinositol, which are important constituents in the whole cells of L. starkeyi, was detected but they were minor constituents.