Enzymatic hydrolysis and characterization of lignocellulosic biomass exposed to electron beam irradiation

► A perennial hybrid grass was characterized and exposed to 0, 75, 150 and 250kGy of electron beam irradiation (EBI). ► Enzymatic hydrolysis of the EBI exposed samples showed significantly higher reducing sugar and glucose yields compared to control. ► IR crystallinity index and degree of crystallinity was lower for the treated samples than control. ► A strong negative correlation between degree of crystallinity and glucose yield was observed. ► The biomass sample used showed properties suitable as a fuel crop. Pretreatment of lignocellulosic biomass has been taken up as a global challenge as it comprises a large renewable source of fermentable sugars. In this study, effect of electron beam irradiation (EBI) on a hybrid grass variety investigated as a biomass pretreatment method. Dry biomass samples after characterization were exposed to EBI doses of 0, 75, 150 and 250kGy. The pretreated biomass samples were enzymatically hydrolyzed using Trichoderma reesei ATCC 26921 cellulase for 144h. The enzyme loadings were 15 and 30FPU/g of biomass. The structural changes and degree of crystallinity of the pretreated biomass were studied by FTIR, XRD and SEM analyses. The lignocellulosic biomass sample showed 12.0% extractives, 36.9% cellulose, 28.4% hemicellulose, 11.9% lignin and 8.6% ash. Significant improvements in the reducing sugar and glucose yields were observed in the hydrolysate of EBI pretreated biomass compared to the control. In 250kGy exposed samples 79% of the final reducing sugar yield was released within 48h of hydrolysis at an enzyme loading rate of 30FPU/g of biomass. The IR crystallinity index calculated from the FTIR data and degree of crystallinity (XRD) decreased in the EBI treated samples. A significant negative correlation was observed between degree of crystallinity and the glucose yield from enzymatic hydrolysis.