Multi-component cocktail designing to develop a cost effective second generation bioconversion technology

Abstract

In this study, the recombinant fungal auxiliary and accessory enzymes derived from thermophilic/thermotolerant fungi and heterologously expressed in methylotrophic yeast Pichia pastoris X33 were evaluated to modulate the hydrolytic efficiency of most advanced cellulase preparation (i.e. Cellic CTec3). The saccharification of diluted acid pre-treated unwashed rice straw slurry obtained from PRAJ and IOCL Industries was carried out using combinations of recombinant proteins & Cellic CTec3, in which the recombinant proteins of Scytalidium thermophilum CM-4T, PMO9D_SCYTH (LPMO), XYL43B_SCYTH (β-xylosidase) and FAED_SCYTH (feruloyl esterase) were found to enhance the saccharification at maximum level when they were supplemented to the Cellic CTec3 (~2.3 mg protein/g substrate) preparation. Employing simplex-lattice mixture design an optimized cocktail of PMO9D_SCYTH, XYL43B_SCYTH & FAED_SCYTH and Cellic CTec3 was designed for saccharification. It was found that the mixture containing [PMO9D_SCYTH: 33.4%; XYL43B_SCYTH: 33.4%; & FAED_SCYTH: 33.4%] optimally hydrolyzed unwashed acid steam pretreated rice straw slurry obtained from PRAJ Industry, showed 70.39% saccharification efficiency (glucan+xylan), while mixture containing [PMO9D_SCYTH: 16.70%; XYL43B_SCYTH: 16.70%; & FAED_SCYTH: 66.70%] was found optimum for the hydrolysis of unwashed rice straw slurry obtained from IOCL Industry showing 84.46% saccharification efficiency (glucan+xylan).