Extracellular overexpression of chitosanase from Bacillus sp. TS in Escherichia coli

Zhanping Zhou, Shuangzhi Zhao, Shouquan Wang, Xiaoman Li, Li Su, Yanhe Ma, Jian Li, Jiangning Song

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14 Citations (Scopus)

Abstract

The chitosanase gene from a Bacillus sp. strain isolated from soil in East China was cloned and expressed in Escherichia coli. The gene had 1224 nucleotides and encoded a mature protein of 407 amino acid residues. The optimum pH and temperature of the purified recombinant chitosanase were 5.0 and 60 ?C, respectively, and the enzyme was stable below 40 ?C. The Km, Vmax, and specific activity of the enzyme were 1.19 mg mL?1, 674.71 ?mol min?1 at 50 ?C, and 555.3 U mg?1, respectively. Mn2+ was an activator of the recombinant chitosanase, while Co2+ was an inhibitor. Hg2+ and Cu2+ inhibited the enzyme at 1 mM. The highest level of enzyme activity (186 U mL?1) was achieved in culture medium using high cell-density cultivation in a 7-L fermenter. The main products of chitosan hydrolyzed by recombinant chitosanase were (GlcN)3?6. The chitosanases was successfully secreted to the culture media through the widely used SecB-dependent type II pathway in E. coli. The high yield of the extracellular overexpression, relevant thermostability, and effective hydrolysis of commercial grade chitosan showed that this recombinant enzyme had a great potential for industrial applications.
Original languageEnglish
Pages (from-to)3271 - 3286
Number of pages16
JournalApplied Biochemistry and Biotechnology - Part A Enzyme Engineering and Biotechnology
Volume175
Issue number7
DOIs
Publication statusPublished - 2015

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