A bifunctional cellulase-xylanase of a new Chryseobacterium strain isolated from the dung of a straw-fed cattle

文献类型： 外文期刊

第一作者： Miao, Renyun

作者： Miao, Renyun;Liu, Tianhai;Li, Yuhui;He, Jiabei;Peng, Weihong;Gan, Bingcheng;Huang, Zhongqian;Tan, Hao;Miao, Renyun;Liu, Tianhai;Yang, Lufang;Yang, Yumin;Chen, Chunxiu;Lei, Jianrong;Peng, Weihong;Gan, Bingcheng;Huang, Zhongqian;Li, Yuhui;He, Jiabei;Sun, Qun

作者机构：

期刊名称：MICROBIAL BIOTECHNOLOGY （ 影响因子：5.813； 五年影响因子：6.559 ）

ISSN： 1751-7915

年卷期： 2018 年 11 卷 2 期

页码：

收录情况： SCI

摘要： A new cellulolytic strain of Chryseobacterium genus was screened from the dung of a cattle fed with cereal straw. A putative cellulase gene (cbGH5) belonging to glycoside hydrolase family 5 subfamily 46 (GH5_46) was identified and cloned by degenerate PCR plus genome walking. The CbGH5 protein was overexpressed in Pichia pastoris, purified and characterized. It is the first bifunctional cellulase-xylanase reported in GH5_46 as well as in Chryseobacterium genus. The enzyme showed an endoglucanase activity on carboxymethylcellulose of 3237molmin(-1)mg(-1) at pH 9, 90 degrees C and a xylanase activity on birchwood xylan of 1793mol min(-1)mg(-1) at pH 8, 90 degrees C. The activity level and thermophilicity are in the front rank of all the known cellulases and xylanases. Core hydrophobicity had a positive effect on the thermophilicity of this enzyme. When similar quantity of enzymatic activity units was applied on the straws of wheat, rice, corn and oilseed rape, CbGH5 could obtain 3.5-5.0x glucose and 1.2-1.8x xylose than a mixed commercial cellulase plus xylanase of Novozymes. When applied on spent mushroom substrates made from the four straws, CbGH5 could obtain 9.2-15.7x glucose and 3.5-4.3x xylose than the mixed Novozymes cellulase+xylanase. The results suggest that CbGH5 could be a promising candidate for industrial lignocellulosic biomass conversion.

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