A yeast isolated from cashew apple juice and its ability to produce first- and second-generation ethanol

Abstract

The aim of this study was to isolate and identify an indigenous yeast from cashew apple juice (CAJ) and then use it in the production of first- and second-generation ethanol, using CAJ and the enzymatic hydrolysate of cashew apple bagasse (MCAB-OH), respectively. The isolated yeast was identified as belonging to the genus Hanseniaspora. Afterward, the effect of the medium initial pH on the production of ethanol from CAJ was evaluated in the range of 3.0 to 5.5, with its maximum ethanol production of 42 g L−1 and YP/S of 0.44 g g−1 and 96 % efficiency. The effect of temperature (28–38 °C) on ethanol production was evaluated in a synthetic medium, and no difference in ethanol production in the temperature range evaluated (28–36 °C) was observed. At 32 °C, the yield, concentration, efficiency, and productivity of ethanol when using the CAJ medium were higher when compared to the results achieved for the synthetic medium. Regarding second-generation ethanol, the results showed that the yeast produced 24.37 g L−1 of ethanol with an efficiency of 80.23 % and a productivity of 4.87 g L−1 h−1 at 5 h. Therefore, Hanseniaspora sp., isolated from CAJ, is a promising microorganism for the production of first- and second-generation ethanol.