Production, purification and characterization of an alkaliphilic endo-β-1,4-xylanase from a microbial community EMSD5

In this study, a novel alkaliphilic extracellular endo-beta-1,4-xylanase was purified from the culture filtrate of microbial community EMSD5, which could grow in liquid culture fermentation under static condition with corn stover as inducement. Single step purification was achieved using anion exchange chromatography. The purified enzyme showed a single band on SDS polyacrylamide gel electrophoresis (SDS-PAGE) with an apparent molecular weight of 22 kDa and pi of 7.1. Stimulation of the activity by beta-mercaptoethanol, and dithiotheritol (DTT) was observed. Moderately thermostable xylanase showed optimum activity at 50 degrees C in pH 8.0. 16S rDNA clone library analysis indicated this community was mainly composed of bacteria related to genera Clostridium, Acinetobacter, Bacteroides, Lysinibacillus and Dysgonomonas. The present work reports for the first time the purification and characterization of an alkaliphilic xylanase from a microbial community, and the alkaliphilicity and moderate thermostability of this xylanase may have potential implications in pulp and paper industries. (c) 2008 Elsevier Inc. All rights reserved.