INFLUENCE OF ETHANOL AND TEMPERATURE ON THE CELLULAR FATTY-ACID COMPOSITION OF ZYGOSACCHAROMYCES-BAILII SPOILAGE YEASTS

Changes in the fatty acid profile of Zygosaccharomyces bailii strains, isolated from different sources, after growth at increasing concentra tions of ethanol and/or decreasing temperatures were determined. Diffe rences in fatty acid composition between Zygosaccharomyces bailii stra ins at standard conditions (25 degrees C, 0% initial ethanol) were obs erved and could be related to ethanol tolerance. Zygosaccharomyces bai lii strain isolated from wine showed the highest ethanol tolerance in relation to growth rate. Surprisingly, an increase in ethanol concentr ation or a decrease in growth temperature caused a decrease in the deg ree of unsaturation of total cellular fatty acids. On the other hand, the mean chain length increased (high ethanol concentration) or decrea sed (low temperature) depending on the stress factor. When both stress situations (high ethanol concentration and low temperature) were pres ent at the same time, the degree of unsaturation remained approximatel y constant. With decreasing temperatures, the C16/C18 ratio increased in studies of initial ethanol content below 5%, and above 5% ethanol, decreased.