A novel bifunctional glucanase exhibiting high production of glucose and cellobiose from rumen bacterium.

Autor: Cao JW; Key Laboratory of Molecular Animal Nutrition, Ministry of Education, Zhejiang University, Hangzhou 310058, China; Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China., Deng Q; Key Laboratory of Molecular Animal Nutrition, Ministry of Education, Zhejiang University, Hangzhou 310058, China; Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China., Gao DY; Key Laboratory of Molecular Animal Nutrition, Ministry of Education, Zhejiang University, Hangzhou 310058, China; Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China; College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo 315100, China., He B; State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China., Yin SJ; College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo 315100, China., Qian LC; Key Laboratory of Molecular Animal Nutrition, Ministry of Education, Zhejiang University, Hangzhou 310058, China., Wang JK; Key Laboratory of Molecular Animal Nutrition, Ministry of Education, Zhejiang University, Hangzhou 310058, China; Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China. Electronic address: jiakunwang@zju.edu.cn., Wang Q; Key Laboratory of Molecular Animal Nutrition, Ministry of Education, Zhejiang University, Hangzhou 310058, China; Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China; College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo 315100, China. Electronic address: Emirate14@zju.edu.cn.
Jazyk: angličtina
Zdroj: International journal of biological macromolecules [Int J Biol Macromol] 2021 Mar 15; Vol. 173, pp. 136-145. Date of Electronic Publication: 2021 Jan 19.
DOI: 10.1016/j.ijbiomac.2021.01.113
Abstrakt: Herbivores gastrointestinal microbiota is of tremendous interest for mining novel lignocellulosic enzymes for bioprocessing. We previously reported a set of potential carbohydrate-active enzymes from the metatranscriptome of the Hu sheep rumen microbiome. In this study, we isolated and heterologously expressed two novel glucanase genes, Cel5A-h38 and Cel5A-h49, finding that both recombinant enzymes showed the optimum temperatures of 50 °C. Substrate-specificity determination revealed that Cel5A-h38 was exclusively active in the presence of mixed-linked glucans, such as barley β-glucan and Icelandic moss lichenan, whereas Cel5A-h49 (EC 3.2.1.4) exhibited a wider substrate spectrum. Surprisingly, Cel5A-h38 initially released only cellotriose from lichenan and further converted it into an equivalent amount of glucose and cellobiose, suggesting a dual-function as both endo-β-1,3-1,4-glucanase (EC 3.2.1.73) and exo-cellobiohydrolase (EC 3.2.1.91). Additionally, we performed enzymatic hydrolysis of sheepgrass (Leymus chinensis) and rice (Orysa sativa) straw using Cel5A-h38, revealing liberation of 1.91 ± 0.30 mmol/mL and 2.03 ± 0.09 mmol/mL reducing sugars, respectively, including high concentrations of glucose and cellobiose. These results provided new insights into glucanase activity and lay a foundation for bioconversion of lignocellulosic biomass.
Competing Interests: Declaration of competing interest The authors declared that they have no conflicts of interest to this work.
(Copyright © 2021. Published by Elsevier B.V.)
Databáze: MEDLINE
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