Chemotaxonomic characterization of yeast cells

Yeast species are analyzed on the basis of their lipid composition to evaluate if chemotaxonomic classification of different species is feasible. The cell walls of samples of Baker's and Brewer's yeast are disrupted by smashing the cells with glass beads at low temperatures. The liberated lipids are extracted with chloroform-methanol. Fractionation of the extract into simple lipids and complex lipids (phospholipids) is performed by column chromatography on silica gel. Elution with methanol produces the simple lipids fraction, whereas elution with methanol-chloroform-ammonium hydroxide produces the phospholipid fraction. The latter fraction is analyzed by high-performance liquid chromatography with light-scattering detection. High-temperature capillary gas chromatography of the simple lipids fraction permits the separation of waxes, sterols, squalene, sterol esters, free fatty acids, monoglycerides, diglycerides, and triglycerides.