Hybrid process for ethanol production from rice straw.

A hybrid process for the fermentation of rice straw hydrolysates into ethanol was designed to simultaneously utilize cellulose and hemicellulose fractions of the agro-residue. The process involved dilute acid hydrolysis (for obtaining C-5 sugars) followed by enzymatic saccharification of cellulose enriched fraction with crude cellulase produced by mixed cultures of Trichoderma reesei Rut C-30 and Aspergillus ochraceus IMI 317911. The fermentation medium containing acid and enzymatic hydrolysate mixture of pentoses and hexoses monomers was fermented with yeast coculture of Saccharomyces cerevisiae and Pachysolen tannophilus resulting in 295.0 ml ethanol/kg of rice straw. The hybrid process resulted in an efficient utilization of both cellulosic and hemicellulosic components of the rice straw for ethanol production.