Potential of killer yeasts utilization for “cachaça” production

Abstract

Two hundred and thirty yeasts were isolated from “cachaça” sugarcane juice and evaluated for the presence of killer phenotype. Sixteen (7.0%) isolates were positive for this characteristic. Incubation temperature and pH of cultivation environment influenced killer toxin production. When incubation temperature was 25 °C all isolates produced toxin at pH 4.2; 4.5 and 5.0. However, killer activity was not detected nor when microorganisms were growth at pH 3.0, nor when incubation temperature was raised above 30 °C. Isolates ability to ferment sugarcane juice and ethanol production was also tested. The fermentation yield of isolate 188 was 45.8%, with 85.1% of fermentative efficiency. The killer character presence and fermentation characteristics of isolate 188 show that it is a promising microorganism to be used on fermentative processes for ethanol production.