Biochemical and molecular characterization of Saccharomyces cerevisiae strains obtained from sugar-cane juice fermentations and their impact in “cachaça” production

Saccharomyces cerevisiae strains from different regions of Minas Gerais, Brazil, were isolated and characterized aiming at the selection of starter yeasts to be used in the production of cachac¸a, the Brazilian sugar cane spirit. The methodology established took into account the screening for biochemical traits desirable in a yeast cachaça producer, such as no H2S production, high tolerance to ethanol and high temperatures, high fermentative capacity, and the abilities to flocculate and to produce mycocins. Furthermore, the yeasts were exposed to drugs such as 5,5_,5_-trifluor-D,L-leucine and cerulenin to isolate those that potentially overproduce higher alcohols and esters. The utilization of a random amplified polymorphic DNA-PCR method with primers based on intron splicing sites flanking regions of the COX1 gene, as well as microsatellite analysis, was not sufficient to achieve good differentiation among selected strains. In contrast, karyotype analysis allowed a clear distinction among all strains. Two selected strains were experimentally evaluated as cachac¸a producers. The results suggest that the selection of strains as fermentation starters requires the combined use of biochemical and molecular criteria to ensure the isolation and identification of strains with potential characteristics to produce cachaça with a higher quality standard.AGRO - ENOSAFE, no. 762.Conselho Nacional de Desenvolvimento Cientíico e Tecnológico of Brazil - CNPq; process 300998/89-9 [R.L.B.]; process 490717/04-7 [CNPq/Grices]; process 301255/01-6 [L.G.F.]).Instituto Nacional de Investigação Agrária.Fundação para a Ciência e Tecnologia.POCI 2010 - FEDER/FCT, POCI/AGR/56102/2004.Fundação de Amparo à Pesquisa do Estado de Minas Gerais - Process EDT-2080/03.Fundação de Capacitação de Pessoal de Nível Superior from the Ministry of Education, Universidade Federal de Ouro Preto