TEMPERATURE ADAPTATION IN YEASTS - THE ROLE OF FATTY-ACIDS

Studies on the yeasts Candida oleophila, Candida utilis, Lipomyces starkeyi, Rhodosporidium toruloides and Saccharomyces cerevisiae revealed the existence of three different temperature adaptation responses involving changes in fatty acid composition. These conclusions were drawn by determining the growth rates, total cellular fatty acid content, fatty acid composition, degree of unsaturation, and the mean chain length of fatty acids over a range of growth temperatures. Within temperatures permitting growth, there were no changes in the major fatty acids of any of the yeasts, but the absolute amounts and relative compositions of the fatty acids did alter. In S. cerevisiae there were temperature-induced changes in the mean fatty acid chain length, whereas in R. toruloides there were changes in the degree of unsaturation. C. oleophila, C. utilis and L. starkeyi showed both responses, depending on whether the growth temperature was above or below 20-26°C. Below 20-26°C temperature-dependent changes were observed in the mean chain length whereas above 20-26°C there were changes in the degree of unsaturation.