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

Abstract

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 °C. Eleven of them were able to grow in presence of 15% of ethanol, but only CH7 and PA18 strains grew at 42 °C. Both were selected for evaluation of their fermentative abilities in maguey juice and in a synthetic medium incubated at 30 and 40 °C. Temperature of 40 °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 °C. Both evaluated strains presented a good fermentative capacity and production of volatile compounds, suggesting their potential use as starter cultures in mezcal fermentation.

Keywords: Fermentative capacity; Mezcal fermentation; Saccharomyces cerevisiae; Stress tolerance; Volatile compounds.

Fig. 1

Dendrogram illustrating the similarity of 19 yeast strains based on interdelta PCR patterns. The letters represent the groups with 100% similarity

Fig. 2

Growth and fructose consumption in fermentations performed by CH7 (graphs A and D) and PA18 (graphs B and C) strains. Empty circle indicates fructose concentration in fermentation performed at 30 °C; filled circle indicates logarithm of cell concentration in fermentations performed at 30 °C; empty triangle indicates fructose concentration in fermentations performed at 40 °C; filled triangle indicates logarithm of cell concentration in fermentations performed at 40 °C