Production of Ionic Liquid-tolerant Cellulase Produced by Microbial Consortium and its Application in Biofuel Production

Abstract

To produce biofuels and specialty chemicals via biorefining process, conversion of lignocellulosic biomass to sugars requires both efficient pretreatment and hydrolysis enzymes. Ionic liquids (ILs) are effective solvent for lignocellulosic biomass pretreatment, however the adverse effect of IL to cellulase has been demonstrated. Here, a lignocellulose degrading microbial consortium was newly bred from saline soil in rice paddle field in Thailand by successive subcultivations. To study the IL-tolerant property, activities of partially purified cellulase produced from CT-1 were evaluated in the present of an IL, 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]). At 1 M of [C2mim][OAc], the cellulase activity was remained more than 85.09% of non-IL condition. For application in biogas production, the rice straw residues mixing with activated sludge wastewater prior to anaerobic digestion was investigated by using this CT-1 consortium as inoculums in batch bioreactors. The experimental results showed that the maximum biogas yield (170.92 mL/g-VS) was obtained. These properties demonstrated that this microbial consortium is potential to be applied for lignocellulose conversion to fuel and other industrial chemicals. © 2016 The Authors. Published by Elsevier Ltd.