The pre-addition of "blocking" proteins decreases subsequent cellulase adsorption to lignin and enhances cellulose hydrolysis

Abstract

The pre-adsorption of non-catalytic/blocking proteins onto the lignin component of pretreated biomass has been shown to significantly increase the effectiveness of subsequent enzyme-mediated hydrolysis of the cellulose by limiting non-productive enzyme adsorption. Layer-by-layer adsorption of non-catalytic proteins and enzymes onto lignin was monitored using Quartz Crystal Micro balancing combined with Dissipation monitoring (QCM-D) and conventional protein adsorption. These methods were used to assess the interaction between soft/hardwood lignins, cellulases and the three non-catalytic proteins BSA, lysozyme and ovalbumin. The QCM-D analysis showed higher adsorption rates for all of the non-catalytic proteins onto the lignin films as compared to cellulases. This suggested that the "blocking" proteins would preferentially adsorb to the lignin rather than the enzymes. Pre-incubation of the lignin films with blocking proteins resulted in reduced adsorption of cellulases onto the lignin, significantly enhancing cellulose hydrolysis.

Keywords: Cellulase; Langmuir adsorption; Lignin; Non-catalytic proteins; Non-productive binding; QCM-D.