NaOH Pretreatment and Enzymatic Hydrolysis of Saccharum spontaneum for Reducing Sugars Production

Abstract

Ethanol from lignocellulosic material is the second generation biofuel production, which includes different initial steps of pretreatment and hydrolysis to form fermentable sugars. The aim of this study was to utilize Saccharum spontaneum (Kans grass, a perennial grass) for NaOH pretreatment and further hydrolysis with on-site produced cellulase enzyme that minimizes the cost of the overall process of bioethanol synthesis. Five percent (w/v) Kans grass was first pretreated with different concentrations of NaOH (0.5, 1. 1.5, and 2% w/v) at variable durations of time period (30, 60, 90, and 120 min) at 121°C. The pretreated biomass was further supplied with a crude mixture of cellulase enzyme (20 units/g biomass) obtained from Trichoderma reesei for saccharification. The crude mixture of enzyme is composed with CMCase, FPAse, and xylanase activities 1.41, 1.12, and 6.23, respectively. The best condition for total reducing sugars (350 mg/g) was found to be at 0.5% NaOH with 120°C where 70.75% of lignin removal was obtained and holocellulose (total carbohydrate) content was increased from 64.7 to 79.61%.