Journal of Microbiology

Research Support, Non-U.S. Gov't

Cel8H, a Novel Endoglucanase from the Halophilic Bacterium Halomonas sp. S66-4: Molecular Cloning, Heterogonous Expression, and Biochemical Characterization: Xiaoluo Huang , Zongze Shao , Yuzhi Hong , Ling Lin , Chanjuan Li , Fei Huang , Hui Wang , Ziduo Liu; J. Microbiol. 2010;48(3):318-324. Published online June 23, 2010; DOI: https://doi.org/10.1007/s12275-009-0188-5

Abstract: A recombinant Escherichia coli clone expressing an endoglucanase was identified from a genomic library of the halophilic bacterium Halomonas sp. S66-4, and the enzyme was designated Cel8H. The cel8H gene consisted of 1,053 bp and encoded 350 amino acids sharing the highest identity of 48% to other known endoglucanases. The protein was expressed in E. coli BL21 (DE3) and purified to homogeneity. The purified recombinant enzyme had an optimal activity of 4.9 U/mg at pH 5 and 45°C toward the substrate carboxymethylcellulose. It exhibited extraordinary properties which differed from endoglucanases reported previously at the point of high salt tolerance above 5 M, simultaneously with high pH stability at pH 4-12 and high temperature stability at 40-60°C. Various substrate tests indicated that the enzyme hydrolyzes β-1,4-glucosidic bonds specifically.

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