Genome sequence and chitinases repertoire of the Chitinibacter sp. strain GC72: Heterologous expression and characterization of the chitinase (Chi1) for degradation of chitinous waste

Alei Zhang; Runke Wang; Xi Zhou; Quanzhen Liu; Xin Zhang; Feifei Chen; Kequan Chen

doi:10.1016/j.ijbiomac.2025.145867

Genome sequence and chitinases repertoire of the Chitinibacter sp. strain GC72: Heterologous expression and characterization of the chitinase (Chi1) for degradation of chitinous waste

Int J Biol Macromol. 2025 Jul 11:145867. doi: 10.1016/j.ijbiomac.2025.145867. Online ahead of print.

Authors

Alei Zhang¹, Runke Wang², Xi Zhou², Quanzhen Liu², Xin Zhang², Feifei Chen³, Kequan Chen¹

Affiliations

¹ College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China; State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, China.
² College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China.
³ College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China; State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, China. Electronic address: feifeichen@njtech.edu.cn.

PMID: 40653235
DOI: 10.1016/j.ijbiomac.2025.145867

Abstract

In this work, a GH18 chitinase (Chi1) with highly hydrolytic activity was identified from Chitinibacter sp. GC72 and successfully cloned and expressed in Escherichia coli BL21(DE3). The recombinant Chi1 exhibited specific activities of 362.6 U/mg against colloidal chitin and 56.7 U/mg against raw α-chitin. Analysis of hydrolysis pattern showed that Chi1 is a multifunctional chitinase, which mainly exhibited processive exo-acting activity with some endo-acting and N-acetyl glucosaminidase activities. Structural analysis and molecular docking were conducted to explore the potential mechanism underlying the highly and multiple activities. Furthermore, Chi1 was utilized to convert raw α-chitin into reducing sugar affording 48.6 % (w/w) yield of total sugar with a 1:4 M ratio of NAG to NAG₂, while also displaying hydrolysis activity to chitinous biomass with 4.1 % sugar yield. This study provides a potent chitinase to hydrolyze chitinous resource with unusual product pattern, showing great potential for further industrial applications.

Keywords: Chitin; Chitinase; Depolymerization; Enzyme identification; N,N′-diacetylchitobiose; N-acetyl glucosamine.