Effect of Subsequent Dilute Acid and Enzymatic Hydrolysis on Reducing Sugar Production from Sugarcane Bagasse and Spent Citronella Biomass

This work was aimed at investigating the effect of process parameters on dilute acid pretreatment and enzymatic hydrolysis of spent citronella biomass (after citronella oil extraction) and sugarcane bagasse on total reducing sugar (TRS) yield. In acid pretreatment, the parameters studied were acid concentration, temperature, and time. At the optimized condition (0.1 M H2SO4, 120°C, and 120 min), maximum TRS obtained was 452.27 mg·g−1 and 487.50 mg·g−1 for bagasse and citronella, respectively. Enzymatic hydrolysis of the pretreated biomass using Trichoderma reesei 26291 showed maximum TRS yield of 226.99 mg·g−1 for citronella and 282.85 mg·g−1 for bagasse at 10 FPU, 50°C, and 48 hr. The maximum crystallinity index (CI) of bagasse and citronella after acid pretreatment obtained from X-ray diffraction analysis was 64.41% and 56.18%, respectively. Decreased CI after enzymatic hydrolysis process to 37.28% and 34.16% for bagasse and citronella, respectively, revealed effective conversion of crystalline cellulose to glucose. SEM analysis of the untreated and treated biomass revealed significant hydrolysis of holocellulose and disruption of lignin.