ИСТИНА

The mycelial fungus Penicillium verruculosum (anamorph: Talaromyces verruculosum) produces a complex of highly active enzymes for the degradation of cellulose as the abudant polysaccharide of the plant cell wall. This complex consists of classical hydrolytic enzymes for cleavage of the main chain of cellulose: exo- and endo-cellulases (cellobiohydrolases (CBHs) and 1,4--glucanases (EGs)) and beta-glucosidase (BG), which carries out terminal hydrolysis of cellobiose to glucose. The recent discovery of copper-dependent lytic polysaccharide mono-oxygenases (LPMOs) has opened up a broad area of research covering several fields of application. Recently, we also isolated and described a new LPMO - an important component of multienzyme cellulase complexes produced by the fungus P. verruculosum. LPMO is an enhancer of the hydrolytic function of the enzyme cellulolytic complex, because it carries out the oxidative depolymerization of cellulose, acting either on -C1 or on the -C4 atom of the anhydroglucose residue of the polymer chain. Recombinant strains-producers of homologous LPMO and heterologous -glucosidase from Aspergillus niger (BGAn) were obtained on the basis of the host fungus P. verruculosum 537 (niad) using set of genetic engineering approaches. Isolation and determination of the enzyme composition in culture fluid secreted by new recombinant Penicillium verruculosum BG-PMO strain has been сarried out by FPLC methods. Component content showed the presence 47% of CBHI, 13% of EG, 18% of BGAn and 2% of LPMO instead of 56% of СBHI, 10% of EG, 3% of BG and <1% of LPMO in host P. verruculosum 537 strain. Saccharification experiments were conducted with the milled aspen wood as the most popular wood feedstock in Russia. The conversion of the substrate was 35% in the case of the BG-PMO application and 25% when using enzyme preparation based on host strain as a control. Thus, obtained in this work new cellulase preparation, containing the LPMO, opens up broad perspectives for further optimization of multienzyme cocktails for saccharification of lignocellulosic materials.