Properties of Chimeric Polysaccharide Monooxygenase with an Attached Cellulose Binding Module and Its Use in the Hydrolysis of Cellulose-Containing Materials in the Composition of Cellulase Complexes

Abstract

The use of recently discovered polysaccharide monooxygenases (PMO) in the composition of cellulase complexes greatly enhances their saccharification ability. Genetic engineering is used in this work to produce a chimeric enzyme based on the Thielavia terrestris PMO with cellulose binding module (CBM) from the Penicillium verruculosum cellobiohydrolase I attached to the PMO С-terminus via a peptide linker. Chimeric PMO exhibits higher (by 24%) activity toward amorphous cellulose and wider substrate specificity than the initial PMO. As a result of the CBM attachment, chimeric PMO acquires the ability to cleave xylan and carboxymethyl cellulose in addition to cellulose and β-glucan, and its activity toward xyloglucan increases by one order of magnitude. Replacing 10% of the highly active cellulase preparation hBGL2 produced by P. verruculosum with the chimeric PMO while retaining the overall dose of the enzymes with regard to their protein concentration increases the yield of sugars during the hydrolysis of microcrystalline cellulose and powdered aspen wood by 24 and 47%, respectively. In addition, the maximum yield of sugars during wood hydrolysis is achieved in 24 h of reaction time, in contrast to hydrolysis with the indicated preparation without the added PMO, which requires 48 h.