Bahaa Shawky
National Research Centre, Egypt
Title: Pretreatment, Hydrolysis, and Fermentation of Rice Straw to Bioethanol as Biofuel
Biography
Biography: Bahaa Shawky
Abstract
The global rise in energy consumption, predicted increase in energy demands, increasing price, unexpected fluctuations, depletion of reserves, and well-documented drawbacks of fossil fuels; have converged to create an urgent need to develop more sustainable energy systems based on renewable biomass feedstocks. Lignocellulosic materials are particularly attractive as feedstocks for biofuel production because of their relatively low cost, great abundance, and sustainable supply. Lignocelluloses are composed of cellulose, hemicellulose, and lignin in a intricate structure, which is recalcitrant to decomposition. Pretreatment is the crucial and costly unit process to liberate the sugars contained within cellulose fibers embedded in the hetero-matrix of plant cell walls. Therefore, the pretreatment step plays a significant role in a lignocellulosic biorefinery process. The present study highlighted the merits of a new pretreatment called Multipurpose Fiber Expansion (MFEX), where Rice Straw (RS) is treated with steam and carbon dioxide in sequence to make use of the synergistic effects obtained under pressure and moderate temperature for a few minutes and then rapidly releasing the pressure. MFEX is a promising method for pretreating rice straw for bioethanal production. A total reducing sugars of about 630 mg/g dry treated RS was achieved within 24 hours hydrolysis with commercial cellulases. Of this total, about 390 mg/g was glucose, which was rapidly fermented within 24 hours by a genetically-engineered ethanologenic organism Klebsiella oxytoca leading to bioethanol yield of about 370 mg/g dry treated RS. The results have significant implications and future applications regarding to provide a sustainable energy production system.