Bioconversion of pretreated sugarcane bagasse using enzymatic and acid followed by enzymatic hydrolysis approaches for bioethanol production

Abstract

The present study was focused on effective utilization of sugarcane bagasse holocellulose for bioethanol production. Saccharification of sugarcane bagasse was performed by employing two strategies viz. direct enzymatic hydrolysis and acid followed by enzymatic hydrolysis. In first case enzymatic saccharification of ammonia treated sugarcane bagasse was carried out using in house developed cocktail of cellulases-hemicellulases and maximum 614 mg/g reducing sugars were produced. By using second strategy, selective fractionation of hemicellulosic sugars was obtained by dilute acid hydrolysis which yielded 41.19 g/l of reducing sugars with pentoses as the major end product. The residual cellulose rich bagasse after alkali treatment was enzymatically hydrolyzed using commercial cellulases which yielded 571 mg/g of reducing sugars with hexoses as the major product. The sugars produced by both the strategies were used for ethanol production separately by suitable hexoses and pentose utilizing yeast strains. By comparative evaluation, it was revealed that direct saccharification of sugarcane bagasse using in-house developed cocktail of cellulases-hemicellulases was more advantageous as compared to acid-enzymatic hydrolysis for bioethnol production.