title: Characterization of a bifunctional xylanase/endoglucanase from yak rumen microorganisms.
abstract: A new gene, RuCelA, encoding a bifunctional xylanase/endoglucanase, was cloned from a metagenomic library of yak rumen microorganisms. RuCelA showed activity against xylan and carboxymethylcellulose (CMC), suggesting bifunctional xylanase/endoglucanase activity. The optimal conditions for xylanase and endoglucanase activities were 65°C, pH 7.0 and 50°C, pH 5.0, respectively. In addition, the presence of Co(+) and Co(2+) can greatly improve RuCelA's endoglucanase activity, while inhibits its xylanase activity. Further examination of substrate preference showed a higher activity against barley glucan and lichenin than against xylan and CMC. Using xylan and barley glucan as substrates, RuCelA displayed obvious synergistic effects with β-1,4-xylosidase and β-1,4-glucosidase. Generation of soluble oligosaccharides from lignocellulose is the key step in bioethanol production, and it is greatly notable that RuCelA can produce xylo-oligosaccharides and cello-oligosaccharides in the continuous saccharification of pretreated rice straw, which can be further degraded into fermentable sugars. Therefore, the bifunctional RuCelA distinguishes itself as an ideal candidate for industrial applications.
authors: State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, People's Republic of China.
authors: Lei
authors: L
authors: Chang
authors: Mozhu
authors: M
authors: Ding
authors: Lei
authors: L
authors: Bao
authors: Yingzhi
authors: Y
authors: Chen
authors: Jungang
authors: J
authors: Zhou
authors: Hong
authors: H
authors: Lu
mesh_terms: D000818:Animals; D056804:Biofuels; D002266:Carboxymethylcellulose Sodium / Q000378:metabolism; D002417:Cattle; D002480:Cellulase / Q000235:genetics* / Q000378:metabolism*; D003001:Cloning, Molecular; D003035:Cobalt / Q000378:metabolism; D003067:Coenzymes / Q000378:metabolism; D000431:Ethanol / Q000378:metabolism; D054892:Metagenome; D008969:Molecular Sequence Data; D012417:Rumen / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D013379:Substrate Specificity; D014990:Xylans / Q000378:metabolism; D014995:Xylosidases / Q000235:genetics* / Q000378:metabolism*
chemical_list: D056804:Biofuels; D003067:Coenzymes; D014990:Xylans; D003035:Cobalt; D000431:Ethanol; D014995:Xylosidases; D002480:Cellulase; D002266:Carboxymethylcellulose Sodium