Enzyme mediated biomass pretreatment and hydrolysis: a biotechnological venture towards bioethanol production

Abstract

Biobased processes are gaining major interest worldwide with considerable efforts now being applied to developing efficient technologies for bioresource utilization. Enzymes produced from microorganisms act as a green route for lignocellulosic biomass pretreatment. Saacharum spontaneum or Kans grass is a potential lignocellulosic rich in cellulose (38.70%), hemicelluloses (29.00%), and lignin (17.46%). To utilize the major proportion of the carbohydrates such as cellulose and hemicelluloses to produce reducing sugar, degradation of lignin is an important prerequisite of the complete bioethanol production process. In the present work, an enzymatic pretreatment process for lignin degradation or delignification has been optimized through response surface methodology (RSM) based on central composite design (CCD). The maximum delignification recorded was 81.67% at 6 h upon monitoring the lignin content of 17.46%. The effectiveness of the enzymatic pretreatment process was investigated through various microscopic and spectroscopic tools as well through porosity analysis that evidenced the specific action of enzyme on lignin. Moreover, the efficacy of enzymatic pretreatment process on enzymatic hydrolysis was studied through optimization based on central composite design. The maximum reducing sugar obtained was 500.30 mg g⁻¹ at 5.30 h of incubation time which indeed supporting the potential of enzymatic mode of biomass pretreatment.