Ester Formation by Saccharomyces cerevisiae During Fermentation

During 2005/06 we monitored kinetics of ester production for seven different commercial yeast strains. Using headspace SPME combined with gas chromatographic analysis we observed significant differences among the strains with respect to rate of ester accumulation and maximum and final levels of esters formed. Interestingly, patterns of ester production also depended on the individual esters monitored. For example, production of ethyl acetate varied significantly with yeast strain, while production of hexyl acetate was similar among the strains studied. These results will now be combined with biotechnological tools that will allow us to monitor gene expression and enzyme activity in these strains. These studies will allow us to better understand the factors influencing flavor formation in Saccharomyces cerevisiae fermentations.