Ethanol production from sugarcane bagasse pre-treated by steam explosion

Abstract

Bioethanol is an alternative renewable fuel that can be produced from cellulosic biomass by hydrolysis and fermentation based processes. Sugarcane bagasse constitutes a potential lignocellulosic substrate for bioethanol production, since it has high sugars content and is a renewable, cheap and readily available feedstock. In this work, steam explosion pre-treatment at different temperatures (200°C, 215°C and 230°C) for 5 min was evaluated on sugarcane bagasse for ethanol production by simultaneous saccharification and fermentation (SSF). Sugar recovery in the solid and liquid fraction obtained after pretreatment and the enzymatic digestibility of the pretreated material were used to determine the optimum temperature, 215°C for 5 min, which resulted in an overall glucose yield of 86.8% of the content in raw material. The solid fraction of sugarcane bagasse pretreated at 215oC was submitted to SSF at increasing solid loading and the effect of xylanase supplementation and a presaccharification step was assessed. The highest final ethanol concentration (56.3gL -1 ) was achieved with SSF supplemented with xylanase enzyme at 20% of solid concentration. Ethanol yields exceeded 0.30g per gram of glucose in all the conditions tested. The results obtained demonstrate the effectiveness of steam explosion in the treatment of sugarcane bagasse fibre.