Biological saccharification by Clostridium thermocellum and two-stage hydrogen and methane production from hydrogen peroxide-acetic acid pretreated sugarcane bagasse

The present work aimed at establishing an efficient degradation and energy recovery system form sugarcane bagasse (SCB) through hydrogen peroxide-acetic acid (HPAC) pretreatment, thermophilic hydrogen production and mesophilic methane production. The degradation ratio of HPAC pretreated SCB (HPAC-SCB, 2%, w/v) exceeded 90% under the biological hydrolysis of C. thermocellum without enzyme addition. The hydrogen yield in the co-culture fermentation of T. thermosaccharolyticum and C. thermocellum from HPAC-SCB (2%, w/v) reached 226 mL/g substrate. The long-term hydrogen fermentation was successfully established with 1.59 L/(L.d), 0.159 L/g substrate for average hydrogen productivity and yield, respectively. Methane production of 0.341 L/g COD (chemical oxygen demand) added was recovered by semi-continuous methane fermentation from hydrogen-producing effluent at 12 days of hydraulic retention time (HRT). Average energy recovery of 8.79 MJ/kg SCB was obtained under the optimal conditions. The present work indicated the promising application of the established process in valorization of lignocellulosic bio-waste. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.