Dilute Acid Pretreatment of Bamboo for Fermentable Sugar Production

Abstract

Biochemical conversion of lignocellulosic biomass to ethanol provides a sustainable energy production system. Bamboo is a fast growing woody grass that has great potential to be used as a domestic feedstock for fuel ethanol production. It consists of about 40% cellulose, and 27% hemicelluloses. In this investigation, bamboo (Dendrocalamus asper) was pretreated with dilute sulfuric acid prior to enzymatic hydrolysis process to produce fermentable sugars. The amount of dry feedstock solid/liquid loading at 10% w/w was pretreated in an autoclave at different temperatures (120, 140°C) with different residence times (30, 60, 90 min) and different sulfuric acid concentrations (0.6, 0.9, 1.2% w/w). Maximum glucose and xylose yields were achieved at 140°C, 1.2% sulfuric acid concentration and 90 min. After enzymatic saccharification with cellulase and β-glucosidase at the same pretreatment conditions, the yields of total reducing sugars were found to be low (56 mg/g). On the other hand, the maximum yields of total reducing sugar (85 mg/g) were obtained for the pretreatment conditions at 120°C, 1.2% sulfuric acid concentration and 60 min. Within these conditions, increasing temperature, residence time and acid concentration led to higher total sugar yields and cellulose conversion rates.