Isolation of Homogeneous Polysaccharide Monooxygenases from Fungal Sources and Investigation of Their Synergism with Cellulases when Acting on Cellulose

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A. G. Bulakhov¹, A. V. Gusakov^1,2*, A. V. Chekushina¹, A. D. Satrutdinov¹, A. V. Koshelev³, V. Yu. Matys³, and A. P. Sinitsyn^1,2

¹Federal Research Center Fundamentals of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia

²Lomonosov Moscow State University, Faculty of Chemistry, 119991 Moscow, Russia; fax: +7 (495) 939-0997; E-mail: avgusakov@enzyme.chem.msu.ru

³Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 142292 Pushchino, Moscow Region, Russia

^* To whom correspondence should be addressed.

Received November 10, 2015; Revision received December 7, 2015

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Lytic polysaccharide monooxygenases (PMO) discovered several years ago are enzymes classified as oxidoreductases. In nature, they participate in microbial degradation of cellulose together with cellulases that belong to the hydrolytic type of enzymes (class of hydrolases). Three PMO from ascomycetes – Thielavia terrestris, Trichoderma reesei, and Myceliophthora thermophila – were isolated and purified to homogeneous state using various types of chromatography. The first two enzymes are recombinant proteins heterologously expressed by the Penicillium verruculosum fungus, while the third is a native PMO secreted by M. thermophila. When acting on microcrystalline cellulose, all these PMOs displayed synergism with the cellulase complex of the P. verruculosum fungus. Replacing 10% of cellulases (by protein concentration) with PMO in the presence of 6.25 mM gallic acid or 2.5 µM of cellobiose dehydrogenase from M. thermophila, used as electron donors for PMO, resulted in the 17-31% increase in the yield of reducing sugars after 24-48 h of the enzymatic reaction.

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KEY WORDS: cellulose biodegradation, ascomycetes, polysaccharide monooxygenase, cellulase complex, synergism

DOI: 10.1134/S0006297916050102

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