2-08: Alkaline hydrogen peroxide pretreatment of sugarcane straw

Sugarcane straw is a lignocellulosic residue that can be used to increase the production of bioethanol through hydrolysis of this material and the fermentation of the resulting sugars. In this work the conditions of a pretreatment with alkaline hydrogen peroxide of sugarcane straw were optimized to improve its susceptibility to enzymatic hydrolysis. A central composite factorial design was performed considering pretreatment time, temperature and hydrogen peroxide concentration as factors and glucose concentration after enzymatic hydrolysis in g/g raw sugarcane straw as the response. Pretreatment was performed using a high solids concentration (15% w/w). The optimal conditions determined for the pretreatment were of 1 h, 60ºC, 0.44 mL (0.65g) of hydrogen peroxide/g straw and pH=11.5. Hemicellulose and lignin solubilizations were of 83.1% and 71.85%, respectively. Enzymatic hydrolysis of straw pretreated at the optimal conditions led to a global glucose yield of 86.97% and hydrolysis conversion of 90.35% when the enzymatic hydrolysis was performed at 50ºC, pH 4.8 and 48h with 3% (w/w) of solids and 15 FPU/g straw of cellulase and 25 CBU/g straw of  β-glucosidase. Sugarcane straw is a promising biomass to the production of cellulosic ethanol and alkaline hydrogen peroxide pretreatment of this material led to high glucose yields after hydrolysis.