Ethanol production using hemicellulosic hydrolyzate and sugarcane juice with yeasts that converts pentoses and hexoses
The use of vegetable biomass as substrate for ethanol production could reduce the existing usage of fossil fuels, thereby minimizing negative environmental impacts. Due to mechanical harvesting of sugarcane, the amount of pointer and straw has increased in sugarcane fields, becoming inputs of great energy potential. This study aimed to analyze the use of hemicellulosic hydrolyzate produced by sugarcane pointers and leaves compared with that of sugarcane juice fermented by yeasts that unfold hexoses and pentoses in the production of second generation biofuel, ethanol. The substrates used for ethanol production composed of either sugarcane juice (hexoses) or hemicellulosic hydrolyzate from sugarcane leaves and pointers (pentoses and hexoses), and the mixture of these two musts. Fermentation was performed in a laboratory scale using the J10 and FT858 yeast strains using 500 ml Erlenmeyer flasks with 180 ml of must prepared by adjusting the Brix to 16 ± 0.3°; pH 4.5 ± 0.5; 30°C; 107 CFU/ml with constant stirring for 72 h, with four replications. Cell viability, budding, buds viability, and ethanol production were evaluated. Among the yeasts, the cell viability was greater for J10. The use of FT858 + J10 was effective in producing ethanol. The hemicellulosic hydrolyzate had low efficiency in ethanol production compared with sugarcane juice.
Key words: Hydrolysis of sugarcane straw and pointers, sugarcane juice, xylose, cell viability, ethanol