A thermophilic chitinase 1602 from the marine bacterium Microbulbifer sp. BN3 and its high-level expression in Pichia pastoris

• Published in: Biotechnology and applied biochemistry Vol. 68; no. 5; p. 1076
• Main Authors: Li, Ren Kuan, Hu, Ya Juan, He, Yu Jie, Ng, Tzi Bun, Zhou, Zhi Min, Ye, Xiu Yun
• Format: Journal Article
• Language: English
• Published: United States 01.10.2021
• Subjects: Alteromonadaceae - enzymology; Chitinases - genetics; Chitinases - metabolism; Gene Expression Regulation, Enzymologic - genetics; Hydrogen-Ion Concentration; Pichia - genetics; Temperature; Microbulbifer sp.BN3; thermophilic chitinase; Pichia pastoris; rChi1602
• ISSN: 1470-8744
• DOI: 10.1002/bab.2027

Chitinases play an important role in many industrial processes, including the preparation of oligosaccharides with potential applications. In the present study, a 1,713 bp gene of Chi1602, derived from a marine bacterium Microbulbifer sp. BN3, encoding a GH18 family chitinase, was expressed at high levels in Pichia pastoris. Distinct from most of the marine chitinases, the recombinant chitinase 1602 exhibited maximal activity at 60 °C and over a broad pH range between 5.0 and 9.0, and was stable at 50 °C and over the pH range 4.0-9.0. The hydrolytic products derived from colloidal chitins comprised mainly (GlcNAc) and GlcNAc, indicating that rChi1602 is a GH18 processive chitinase in conformity with its hypothetical structure. However, rChi1602 showed traces of β-N-acetylglucosaminidase activity on substrates such as powder chitin, chitosan, and ethylene glycol chitin. The thermophilic rChi1602, which manifests adaptation to a wide pH range and can be expressed at a high level in P. pastoris, is advantageous for applications in industrial processes.