Enhanced saccharification efficiency of lignocellulosic biomass of mustard stalk and straw by salt pretreatment

Abstract

Cost effective technologies for bio-ethanol production from lignocellulosic biomass are important to meet India’s need of bioenergy. Mustard stalk and straw (MSS) is an abundant agroresidue of India for enzyme production and saccharification. This study demonstrates the effects of pretreatment processes on MSS with common salt (NaCl) in comparison to hot water and alkali. SEM images revealed loosening of fibers with some distortion of cellular arrangements, increased external surface area and porosity in NaCl treated MSS. In XRD analysis crystallinity index of salt pretreated MSS (61.95%) was higher than untreated (36.84%) biomass. FTIR spectroscopy analysis further supported SEM and XRD data. Saccharification efficiency of salt treated MSS increased to 82% as compared to untreated biomass (16%) with decrease in total lignin content by 26% in comparison. Salt pretreatment appeared as a cheaper and nontoxic alternative to alkali and other expensive and toxic pretreatment processes for bioethanol production from lignocellulosic biomass.