Ethanol Production from Sugarcane Bagasse Pretreated by Steam Explosion

Abstract

Bioethanol is an alternative renewable fuel that can be produced from cellulosic biomass through hydrolysis and fermentation based processes. Sugar- cane bagasse constitutes a potential lignocellulosic substrate for bioethanol production, since it has high sugar content and is a renewable, cheap and readily available feedstock. In this work, steam explosion pretreatment at different temperatures (200°C, 215°C and 230°C) for 5 min was evaluated on sugarcane bagasse for ethanol production by simultaneous sac- charification and fermentation (SSF). Sugar recovery in the solid and liquid fraction obtained after pre - treatment and the enzymatic digestibility of the pre- treated 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 pre - treated at 215°C was submitted to SSF at increasing solid loading and the effect of xylanase supplemen - tation and a presaccharification step was assessed. The highest final ethanol concentration (56.3 g L -1 ) was achieved with SSF supplemented with xylanase enzyme at 20% of solid concentration. Ethanol yields exceeded 0.30 g per gram of glucose in all the con- ditions tested. The results obtained demonstrate the effectiveness of steam explosion in the treatment of sugarcane bagasse fiber.