Mezcal: indigenous Saccharomyces cerevisiae strains and their potential as starter cultures

In this study, 19 indigenous mezcal Saccharomyces cerevisiae strains were screened for their tolerance to grow under different stress conditions and their potential use in fermentation. All strains were able to tolerate pH value of 3, significant levels of glucose (30%), ethanol (12% v/v), and temperature of 37 degrees C. Eleven of them were able to grow in presence of 15% of ethanol, but only CH7 and PA18 strains grew at 42 degrees C. Both were selected for evaluation of their fermentative abilities in maguey juice and in a synthetic medium incubated at 30 and 40 degrees C. Temperature of 40 degrees C had a positive effect on the ethanol production, increasing the productivity and efficiency in maguey fermentation. Ethyl acetate, isobutanol and isoamyl alcohols production was favored at 30 degrees C. Both evaluated strains presented a good fermentative capacity and production of volatile compounds, suggesting their potential use as starter cultures in mezcal fermentation.