Synergistic Action of a Lytic Polysaccharide Monooxygenase and a Cellobiohydrolase from Penicillium funiculosum in Cellulose Saccharification under High-Level Substrate Loading

Abstract

The enzymatic hydrolysis of cellulosic biomass by cellulases continues to be a significant bottleneck in the development of second-generation biobased industries. While increasing efforts are being made to obtain indigenous cellulases for biomass hydrolysis, the high production cost of this enzyme remains a crucial challenge affecting its wide availability for the efficient utilization of cellulosic materials. This is because it is challenging to obtain an enzymatic cocktail with balanced activity from a single host. This report describes the annotation and structural analysis of an uncharacterized lytic polysaccharide monooxygenase (LPMO) gene in Penicillium funiculosum and its impact on biomass deconstruction upon overexpression in a catabolite-derepressed strain of P. funiculosum . Cellobiohydrolase I (CBH1), which is the most important enzyme produced by many cellulolytic fungi for the saccharification of crystalline cellulose, was further overexpressed simultaneously with LPMO. The resulting secretome was analyzed for enhanced LPMO and exocellulase activities and the corresponding improvement in saccharification performance (by ∼20%) under high-level substrate loading using a minimal amount of protein.