Novel buffalo rumen metagenome derived acidic cellulase Cel-3.1 cloning, characterization, and its application in saccharifying rice straw and corncob biomass

Lignocellulosic biomass (LCB) is a prominent option for second-generation biofuels production. Cellulase hydrolyses cellulose, a component of LCB by attacking the beta-1,4-glycosidic bonds, thus liberating mono, di, and oligosaccharides, which subsequently, can be converted to biofuel. In this study, a novel cellulase (Cel-3.1) of 1593 bp which encodes a 530 amino acid protein was identified from buffalo rumen metagenomic fosmid library, and functional expression was achieved through transformation into Esc herichia call. The molecular weight was estimated as 58 kDa on SDS-PAGE. Cel-3.1 belongs to glycosyl hydrolase family-5 (GH-5) and is predicted to have 14 a-helices and 15 beta-strands. The optimal temperature and pH for Cel-3.1 were experimentally determined as 5.0 and 50 degrees C respectively. The synergistic effect of Ca2+ with K+ ions improved Cel-3.1 activity significantly (25%) and 1% Polyethylene Glycol (PEG-400), 1% beta-mercaptoethanol enhanced the relative activity Cel-3.1 by 31.68%, 12.03% respectively. Further, the enzymatic (Cel-3.1) hydrolysis of pretreated rice straw and corncob released 13.41 +/- 026 mg/mL and 15.04 +/- 0.08 mg/mL reducing sugars respectively. High Performance Liquid Chromatography (HPLC), Scanning Electron Microscope (SEM), and Fourier Transformation Infrared spectroscopy (MR) analysis revealed the capability of Cel-3.1 for the breakdown and hydrolysis of both rice straw and corncob to generate various fermentable sugars. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

Lignocellulosic biomass is a prominent option for second-generation biofuels production. A novel cellulase, Cel-3.1, was identified from buffalo rumen and showed potential in hydrolyzing rice straw and corncob to generate fermentable sugars.