文献类型： 外文期刊

作者： Zhou, Yu ¹ ; Wang, Xu ¹ ; Wei, Wei ² ; Xu, Jimin ² ; Wang, Wei ² ; Xie, Zhongwen ¹ ; Zhang, Zhengzhu ¹ ; Jiang, Hongchen; ¹ ;

作者机构： 1.Anhui Agr Univ, Sch Tea & Food Sci Technol, State Key Lab Tea Biol & Utilizat, Hefei 230036, Peoples R China

2.Zhejiang Acad Agr Sci, Inst Qual & Standard Agroprod, Hangzhou 310021, Zhejiang, Peoples R China

3.China Univ Geosci, State Key Lab Biogeol & Environm Geol, Wuhan 430074, Peoples R China

4.Novus Int Shanghai Inc, Shanghai 200080, Peoples R China

关键词： Metagenomic library;Versatile beta-glucanase;Glycoside hydrolase family 9;Transglycosylation;Endoglucanase;Exoglucanases

期刊名称：BIOTECHNOLOGY FOR BIOFUELS （ 影响因子：6.04； 五年影响因子：6.485 ）

ISSN： 1754-6834

年卷期： 2016 年 9 卷

页码：

收录情况： SCI

摘要： Background: Cellulose, an abundant and renewable polysaccharides, constitutes the largest resource for bioconversion of biofuels. Plant polysaccharides hydrolysis is catalyzed by cellulases, which include endoglucanases, exoglucanases, and a-glucosidases. Converting cellulose and hemicellulose to short chains of oligosaccharides by endo-/exoglucanases is the key step for biofuel transformation. Intriguingly, beta-glucanases with transglycosylation activity not only can relieve product inhibition of glucan hydrolysis but also has potential application as biocatalysts for functional materials. Results: Here, a metagenomic fosmid library was constructed from a paddy soil for cellulase screening. One purified clone showing carboxymethylcellulase activity was isolated, and the complete beta-glucanase gene (umcel9y-1) was cloned and overexpressed in Escherichia coli. Phylogenetic analysis indicated that beta-glucanase Umcel9y-1 belonged to the theme C of glycoside hydrolase family 9. Amino acids sequence showed 58.4 % similarity between Umcel9y-1 and its closest characterized reference, cellulase Cel01. Biological characterization showed that Umcel9y-1 was an efficient endoglucanase and also exhibited high activities of exoglucanase and transglycosylation. The transglycosylation products of Umcel9y-1 including sophorose, laminaribiose, and gentiobiose, and transglycosylation was detected under all activated conditions. The order of catalytic efficiency for polysaccharides, cellooligosaccharides, and aryl-beta glycosides was p-nitrophenol-D-cellobioside, barley glucan, cellopentaose, cellotetraose, cellotriose, hydroxyethylcellulose, cellohexose, laminarin, and carboxymethylcellulose, respectively. The barley glucan was the optimal polysaccharides for Umcel9y-1 with K-m and K-cat/K-m values of 13.700 mM and 239.152 s(-1) mM(-1), respectively. Conclusion: Biological characterizations of recombinant Umcel9y-1 showed that the versatile beta-glucanase had efficient endoglucanase activity to barley glucan and also exhibited high activities of exoglucanase and transglycosylation. The optimum conditions of recombinant Umcel9y-1 was pH 6.5-7.0 at 37 degrees C with predominant halotolerance and high-thermal stability. These results indicate that the novel metagenomic-derived beta-glucanase may be a potent candidate for industrial applications.