Cellular Fatty Acid of Soy Yeasts and Osmophilic Yeasts

Abstract

A study was made on the cellular fatty acid composition of yeasts isolated from soy-mash and the other sources.
The cellular fatty acid of all the osmophilic yeasts tested in this work were mainly composed of palmitic, stearic, palmitoleic, oleic and linoleic acids, and any distinguishable difference from those of non-osmophilic Saccharomyces was not detected.
Saccharomyces rouxii which occures predominantly in the fermentation period of soybrewing, and produces the most of alcohol in soy sauce contained a large amount of linoleic acid as a cellular fatty acid. On the other hand, Torulopsis which plays an important role on the ripening process of soy-mash practically had no linoleic acid but contained a long chain fatty acid (24:0). This difference of fatty acid composition between Sacch. rouxii and Torulopsis may be used as a criterion of classification of the two kind of yeasts.
As to the non-osmophilic yeasts isolated from soy-mash, Pichia and Trichosporon contained a smaller quantity of cellular palmitoleic acid. It is interesting to note that Torulopsis famata contained both linoleic and the long chain fatty acid (24:0).
The fatty acid composition of osmophilic yeasts belonging to Sacch. rouxii or Torulopsis isolated from the sources other than soy-mash were similar to those of the corresponding yeasts from soy-mash.
Palmitoleic and linoleic acids of Sacch. rouxii considerably decreased when the yeast was cultured in a medium containing 18 percent of NaC1 without agitation. Whereas, Torulopsis was not practically affected in the fatty acid composition by the culture condition.