Biological pretreatment of cellulose: Enhancing enzymatic hydrolysis rate using cellulose-binding domains from cellulases

Abstract

In this study, cellulose-binding domains (CBDs) of cellulases from Trichoderma reesei were used in a pre-treatment step and were found to effectively reduce the crystallinity of cellulose (both Avicel and fibrous cellulose). This, in turn, led to higher glucose concentrations (up to 25% increase) in subsequent hydrolysis of cellulose using a mixture of cellulases and without the need for any intermediate purification step. CBDs were shown to be active in a range of temperatures (up to 50 degrees C), while cellulase hydrolytic activity was greatly reduced after incubation at 50 degrees C. This was explained by retention of full binding capacity after incubation at 50 degrees C for 15 h. Our findings suggest that CBDs may be a valuable tool in pre-treating cellulose and eventually afford faster enzymatic conversion of cellulose to glucose, thus contributing to more affordable processes in the production of biofuels. (C) 2010 Elsevier Ltd. All rights reserved.