Lipid Production by a Soil Yeast

Abstract

A, soil yeast, hitherto undescribed,. was obtained which produces, on N-deficient medium, watery opaque,colonies, containing cells which are large and nearly, filled with globules of fat. Light, amber-colored spores are produced but; the number is variable[long dash]in some strains up to 16 or more per cell. The spores are formed in a sac-like bud which remains attached to the parent cell. The original granular contents, of the buds;change to spores. The yeast ferments no sugar and produces no pellicle; it does not utilize nitrate or attack gelatin. It grows on various sugars and uses asparagine, (NH4)2SO4 and yeast extract as N-sources. Lipid production is, favored by aeration and low N content. Under favorable conditions, 20-25% 6f the consumed glucose is converted to yeast cells which contain 50-63% lipid (dry basis)., 10-14% of the consumed glucose is recovered as lipid. The lipid content of the cells decreases as the N content of the medium increases. Only a little of the lipid could be extracted from the cells directly with fat solvents, but it became released by hydrolysis with dilute acid.