Two baker's and two brewer's yeast strains of Saccharomyces cerevisiae
were compared. Regarding their cell composition there was almost no d
ifference in proteins and nucleic acids. Differences were observed in
total lipid amounts as well as in lipid composition. Baker's yeasts co
ntained only about one half as much lipids as the brewer's yeasts. Amo
ng phospholipids phosphatidylethanolamine prevailed in all strains tes
ted. The phosphatidylcholine content was almost ten times higher in br
ewer's yeasts whereas the amounts of phosphatidylserine and phosphatid
ylinositol were two to three times higher in baker's yeast strains. Th
e ratio of saturated to unsaturated fatty acids was always lower with
brewer's yeasts. The differences in fatty acid composition were less p
ronounced than the differences in phospholipid composition.