Isolation and characterization of a novel endo-β-1,4-glucanase from a metagenomic library of the black-goat rumen

Revista de microbiologia

Song, Yun-Hee¹  Baek, Jin-Young²  Lee, Kyung-Tai³ 

[1] Chung-Ang University, Ansung, South Korea;Kyonggi University, Suwon, South Korea;National Institute of Animal Science, Rural Development Administration, Wanju, South Korea

关键词: Black goats;    Endo-β;    -1;    4-glucanase;    Glycosyl hydrolase family 5 (GH5);    Metagenomic library;    Rumen.;   

DOI  :  10.1016/j.bjm.2017.03.006

学科分类：农业科学（综合）

来源: Sociedade Brasileira de Microbiologia / Brazilian Society for Microbiology

【 摘 要 】

The various types of lignocellulosic biomass found in plants comprise the most abundant renewable bioresources on Earth. In this study, the ruminal microbial ecosystem of black goats was explored because of their strong ability to digest lignocellulosic forage. A metagenomic fosmid library containing 115,200 clones was prepared from the black-goat rumen and screened for a novel cellulolytic enzyme. The KG35 gene, containing a novel glycosyl hydrolase family 5 cellulase domain, was isolated and functionally characterized. The novel glycosyl hydrolase family 5 cellulase gene is composed of a 963-bp open reading frame encoding a protein of 320 amino acid residues (35.1 kDa). The deduced amino acid sequence showed the highest sequence identity (58%) for sequences from the glycosyl hydrolase family 5 cellulases. The novel glycosyl hydrolase family 5 cellulase gene was overexpressed in Escherichia coli. Substrate specificity analysis revealed that this recombinant glycosyl hydrolase family 5 cellulase functions as an endo-β-1,4-glucanase. The recombinant KG35 endo-β-1,4-glucanase showed optimal activity within the range of 30-50 °C at a pH of 6-7. The thermostability was retained and the pH was stable in the range of 30-50 °C at a pH of 5-7.

【 授权许可】

CC BY-NC