Trehalose accumulation, invertase activity and physiological characteristics of yeasts isolated from 24 h fermentative cycles during the production of artisanal Brazilian cachaça

RESUMO

Trehalose accumulation, invertase activity and physiological characteristics of 86 yeast isolates from short fermentative cycles during the production of cachaça in three artisanal distilleries of the State of Minas Gerais were studied. Among these isolates, 70 percent were able to grow at temperatures between 40 and 42ºC. Only Saccharomyces cerevisiae isolates were able to grow over 40ºC. Lower temperatures (<40ºC) favoured the growth of yeasts such as Candida parapsilosis-like, C. maltosa-like, Kloeckera japonica, S. exiguus and C. bombicola-like. The isolates from all three distilleries were ethanol tolerant, produced invertase, and accumulate trehalose in the presence of glucose. The strains isolated from distillery A presented more resistance to ethanol (around 84.2 percent of the strains were able to grow in the presence of 12 percent ethanol) when compared to the ones from distilleries C and B (9.5 percent and no strain, respectively). The strains of S. cerevisiae isolated from the three distilleries presented a higher capacity to produce invertase and accumulate trehalose in the presence of glucose. Based on the results of thermal and ethanol stress experiments, it was possible to identify strong relationship between intracellular trehalose accumulation and cell viability. The increase in cell viability was even more pronounced when the strains were subjected to a pre-treatment at sublethal temperatures