A Novel GH Family 20 β-N-acetylhexosaminidase With Both Chitosanase and Chitinase Activity From Aspergillus oryzae

Tianle Qu; Chunyue Zhang; Zhen Qin; Liqiang Fan; Lihua Jiang; Liming Zhao

doi:10.3389/fmolb.2021.684086

A Novel GH Family 20 β-N-acetylhexosaminidase With Both Chitosanase and Chitinase Activity From Aspergillus oryzae

Front Mol Biosci. 2021 May 19:8:684086. doi: 10.3389/fmolb.2021.684086. eCollection 2021.

Authors

Tianle Qu¹, Chunyue Zhang¹, Zhen Qin², Liqiang Fan¹, Lihua Jiang¹, Liming Zhao^{1

3}

Affiliations

¹ School of Biotechnology, State Key Laboratory of Bioreactor Engineering, R&D Center of Separation and Extraction Technology in Fermentation Industry, East China University of Science and Technology, Shanghai, China.
² School of Life Science, Shanghai University, Shanghai, China.
³ Shanghai Collaborative Innovation Center for Biomanufacturing Technology (SCICBT), Shanghai, China.

Abstract

Aminooligosaccharides possess various biological activities and can exploit wide applications in food, pharmaceutical and cosmetic industries. Commercial aminooligosaccharides are often prepared by the hydrolysis of chitin and chitosan. In this study, a novel GH family 20 β-N-acetylhexosaminidases gene named AoNagase was cloned from Aspergillus oryzae and expressed in Pichia pastoris. The purified AoNagase had maximal activity at pH 5.5 and 65°C. It exhibited good pH stability in the range of pH 6.0-7.5 and at temperatures below 50°C. AoNagase was capable of hydrolyzing not only colloidal chitosan (508.26 U/mg) but also chitin (29.78 U/mg). The kinetic parameters (K _m and V _max ) of AoNagase were 1.51 mM, 1106.02 U/mg for chitosan and 0.41 mM, 40.31 U/mg for colloidal chitin. To our knowledge, AoNagase is the first GH family 20 β-N-acetylhexosaminidase capable of hydrolyzing both chitosan and chitin. AoNagase is an endo-type β-N-acetylhexosaminidases and can potentially be used for the manufacturing of aminooligosaccharides.

Keywords: aminooligosaccharide; chitin; chitosan; glycoside hydrolase family 20; β-N-acetylhexosaminidase.