Characterization and selection of native yeast isolated from natural fermentation for the production of the artisanal beverage bacanora

Abstract

Bacanora is a Mexican distilled beverage made from agave, similar to tequila and mescal, produced with an artisanal process. Therefore the organoleptic characteristics of different bacanora vary highly. The aim of this study was to characterize and select native yeast involved in this artisanal process of fermentation. An initial pre-selection based upon the phenotypic characteristics of 580 strains of yeast was done, and then with fermentation characteristics with agave juice, to select some strains which satisfy with desirable. The Saccharomyces cerevisiae yeasts produced at the end of the fermentation 8.27 ± 0.24 g/L of biomass, 25.51 ± 1.19 g/L of ethanol, with a volumetric productivity of ethanol of 1.76±0.17 g/L/h. While for the three strains non-Saccharomyces the parameters were 3.86 ± 1.14 g/L, 15.56± 1.68 g/L and 0.484±0.06 g/L/h respectively. In the mixed culture of three S. cerevisiae, all remained at the end, but one of them predominates and of non-Saccharomyces yeasts, Torulaspora delbrueckii was the predominant yeast, this according with PFGE results. The results showed that the native yeasts are adapted to the agave juice used for production of bacanora and these yeasts would contribute to improve the ethanol yields and the organoleptic characteristics of Bacanora.