Zhang A, He Y, Wei G, Zhou J, Dong W, Chen K, Ouyang P. Molecular characterization of a novel chitinase
CmChi1 from
Chitinolyticbacter meiyuanensis SYBC-H1 and its use in
N-acetyl-d-glucosamine production.
Biotechnol Biofuels 2018;
11:179. [PMID:
29983742 PMCID:
PMC6020246 DOI:
10.1186/s13068-018-1169-x]
[Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 06/12/2018] [Indexed: 05/30/2023]
Abstract
BACKGROUND
N-acetyl-d-glucosamine (GlcNAc) possesses many bioactivities that have been used widely in many fields. The enzymatic production of GlcNAc is eco-friendly, with high yields and a mild production process compared with the traditional chemical process. Therefore, it is crucial to discover a better chitinase for GlcNAc production from chitin.
RESULTS
A novel chitinase gene (Cmchi1) cloned from Chitinolyticbacter meiyuanensis SYBC-H1 and expressed in Escherichia coli BL21(DE3) cells. The recombinant enzyme (CmChi1) contains a glycosyl hydrolase family 18 catalytic module that shows low identity (12-27%) with the corresponding domain of the well-characterized chitinases. CmChi1 was purified with a recovery yield of 89% by colloidal chitin affinity chromatography, whereupon it had a specific activity of up to 15.3 U/mg. CmChi1 had an approximate molecular mass of 70 kDa after the sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and its optimum activity for colloidal chitin (CC) hydrolysis occurred at pH 5.2 and 50 °C. Furthermore, CmChi1 exhibited kcat/Km values of 7.8 ± 0.11 mL/s/mg and 239.1 ± 2.6 mL/s/μmol toward CC and 4-nitrophenol N,N'-diacetyl-β-d-chitobioside [p-NP-(GlcNAc)2], respectively. Analysis of the hydrolysis products revealed that CmChi1 exhibits exo-acting, endo-acting and N-acetyl-β-d-glucosaminidase activities toward N-acetyl chitooligosaccharides (N-acetyl CHOS) and CC substrates, behavior that makes it different from typical reported chitinases. As a result, GlcNAc could be produced by hydrolyzing CC using recombinant CmChi1 alone with a yield of nearly 100% and separated simply from the hydrolysate with a high purity of 98%.
CONCLUSION
The hydrolytic properties and good environmental adaptions indicate that CmChi1 has excellent potential in commercial GlcNAc production. This is the first report on exo-acting, endo-acting and N-acetyl-β-d-glucosaminidase activities from Chitinolyticbacter species.
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