Comparison of microbial and sono-assisted alkaline pre-treatment of sugarcane bagasse, followed by one-pot synthesis of microbial extracellular polymeric substance through simultaneous delignification, saccharification, and fermentation

Abstract

Lignocellulosic biomass (LCB) captures a major fraction of agro-industrial wastes that are mostly valorised for the production of second-generation biofuels. The extensive pre-treatment followed by saccharification of LCB restricts its usability for the production of a wide array of bioproducts. This study highlights the performance comparison of sono-assisted alkaline pre-treatment versus microbial pre-treatment of sugarcane bagasse by a no. of analytical techniques such as FTIR, XRD, CHNS, and SEM. Moreover, simultaneous delignification, saccharification and fermentation (SDSF) in one pot is highly desirable for the cost effective and environment friendly production of microbial products. In the present study SDSF was carried out by a cellulolytic bacterium Cellulomonas flavigena, for the production of extracellular polymeric substance (EPS), which is, by chemical nature a biopolymer made up of carbohydrate and protein subunits. The biopolymer was found to have an overall positive charge as analysed by ion exchange chromatography. Two major fractions of molecular weight 237 KDa and 29 KDa were obtained from gel filtration chromatography, in addition to that, the EPS was found to be composed of monosaccharides, D (+) mannosamine and D (+) xylose as identified from high pressure liquid chromatography (HPLC).