Synergistically Degradation of Cellulose by Anlpmo14g, A Fungal Lytic Polysaccharide Monooxygenase from Aspergillus Niger

Abstract The auxiliary active family 9 (AA9) of fungal lytic polysaccharide monooxygenases (LPMOs) can improve the lignocellulosic hydrolysis through an oxidative mechanism. Aspergillus niger is an important industrial producer of glycoside hydrolases, but little research on LPMOs in A. niger have been reported. This study aimed to research the biochemical characteristics of LPMOs from A. niger and the synergy with cellulase on cellulose hydrolysis. Reducing sugar produced when An LPMO14g acted on Carboxyl Methyl Cellulose (CMC), Avicel ® , xylan, filter paper, straw and corn cobs, and MALDI-TOF/TOF mass spectrometry analysis indicated that it oxidatively cleaved the glycosidic bonds of Avicel ® at C1 position. The addition of An LPMO14g into the hydrolysis systems of Avicel® and straw catalyzed by cellulase could increase the yields of reducing sugar by 92.66% and 141.42%, respectively. Homology modeling displayed that the residues H1, H86, Y175, Y24, P83 and Y212 of An LPMO14g played an important role in the catalytic process of cellulose. This study enriches the AA9 LPMO family and provides a promising candidate for the high-efficient enzyme cocktails for lignocellulose degradation.