Tolerance and response of Saccharomyces cerevisiae wine strains to stress treatments

This study evaluated the stress tolerance and stress response of three indigenous Saccharomyces cerevisiae strains and one reference strain against temperature (45, 50, and 55 degrees C) and ethanol (12 and 14 % v/v) stresses over time by assessing the yeast counts and intracellular trehalose content. The maximum decrease in the yeast counts was at 55 degrees C and 14 % ethanol. At 45 degrees C and 14 % ethanol the highest intracellular trehalose content was induced for all strains (P < 0.05). The correlation between the trehalose content and Log N levels of the strains was significant with the correlation coefficient (r) 0.62 and 0.39 for strains 2 and 7 against temperature stress. A strong and significant correlation was also determined with r values for strains 2,7, 47 in response to the ethanol stress, respectively (P < 0.05).