ABSTRACT
In Brazil, spontaneous fermentation and open vessels are still used to produce cachaça (the Brazilian sugarcane spirit) and this fermentation is characterized by mixed cultures with continuous succession of yeast species. This work shows the development of a methodology for isolation of yeasts, particularly Saccharomyces cerevisiae, used in the production of cachaça. According to the proposed strategy, the strains were selected for their ability to adapt to stress conditions encountered during fermentation of the sugarcane juice such as high sucrose concentration; high temperatures and high alcohol concentration; for their capacity to flocculate; and for their higher fermentative ability. For strains with such characteristics, specific procedures were employed to select for 5,5,5-trifluoro-DL-leucine (TFL) and cerulenin-resistant strains, since these characteristics are related to a higher capacity of production of the flavoring compounds isoamyl alcohol and caproic acid, respectively. The effectiveness of such a selection strategy was documented. Taken together, the results obtained present the development of a new strategy to isolate yeast strains with appropriated characteristics to be used in the cachaça industry. Moreover, the results obtained offer an explanation for the great variability in terms of chemical composition found in products obtained even in a single distillery.
