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International Journal of Microbiology
Volume 2017 (2017), Article ID 4018398, 12 pages
Research Article

Gene Expression and Molecular Characterization of a Xylanase from Chicken Cecum Metagenome

1Department of Microbiology, Faculty of Science, Mahidol University, Ratchathewi, Bangkok 10400, Thailand
2Chemical and Petrochemical Research Center, Commission for Research and Industrial Development, Ministry of Industry and Minerals, 10068 Baghdad, Iraq

Correspondence should be addressed to Suthep Wiyakrutta

Received 21 March 2017; Revised 15 May 2017; Accepted 23 May 2017; Published 2 July 2017

Academic Editor: Hugh W. Morgan

Copyright © 2017 Hind AL-Darkazali et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A xylanase gene xynAMG1 with a 1,116-bp open reading frame, encoding an endo-β-1,4-xylanase, was cloned from a chicken cecum metagenome. The translated protein consisted of 372 amino acids including a putative signal peptide of 23 amino acids. The calculated molecular mass of the mature was 40,013 Da, with a theoretical pI value of 5.76. The amino acid sequence of showed 59% identity to endo-β-1,4-xylanase from Prevotella bryantii and Prevotella ruminicola and 58% identity to that from Prevotella copri. has two conserved motifs, DVVNE and TEXD, containing two active site glutamates and an invariant asparagine, characteristic of GH10 family xylanase. The xynAMG1 gene without signal peptide sequence was cloned and fused with thioredoxin protein (Trx.Tag) in pET-32a plasmid and overexpressed in Escherichia coli Tuner™(DE3)pLysS. The purified mature was highly salt-tolerant and stable and displayed higher than 96% of its catalytic activity in the reaction containing 1 to 4 M NaCl. It was only slightly affected by common organic solvents added in aqueous solution to up to 5 M. This chicken cecum metagenome-derived xylanase has potential applications in animal feed additives and industrial enzymatic processes requiring exposure to high concentrations of salt and organic solvents.