Table of Contents
ISRN Microbiology
Volume 2012 (2012), Article ID 517524, 8 pages
http://dx.doi.org/10.5402/2012/517524
Research Article

Thermostable and Alkalistable Xylanases Produced by the Thermophilic Bacterium Anoxybacillus flavithermus TWXYL3

Department of Biological Sciences, Idaho State University, P.O. Box 8007, Pocatello, ID 83209, USA

Received 26 June 2012; Accepted 19 July 2012

Academic Editors: B. Ayo and J. Ruiz-Herrera

Copyright © 2012 Joshua T. Ellis and Timothy S. Magnuson. 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.

Abstract

With the rising cost and finite supply of fossil energy, there is an increasing economic incentive for the development of clean, efficient, and renewable domestic energy. The activities of microorganisms offer the potential conversion of lignocellulosic materials into fermentable sugars, usable for downstream fermentation processes. Strain TWXYL3, a thermophilic facultative anaerobe, was discovered in the Alvord Basin hydrothermal system in Oregon, USA. Phylogenetic analysis of strain TWXYL3 showed it to be 99% similar to the 16S rRNA gene of Anoxybacillus flavithermus WL (FJ950739). A. flavithermus TWXYL3 was shown to secrete a large multisubunit thermostable xylanase complex into the growth medium. Xylanase induction was achieved by resuspending the isolate in a selective xylan-containing medium. Extracellular xylanase activity showed a temperature optimum of 65°C and retained thermostability up to 85°C. Extracellular xylanase activity showed a bimodal pH optimum, with maxima at pH 6 and pH 8. Electrophoretic analysis of the extracellular xylanase shows 5 distinct proteins with xylanase activity. Strain TWXYL3 is the first xylanolytic isolate obtained from the Alvord Basin hydrothermal system and represents a new model system for development of processes where lignocellulosics are converted to biofuel precursors.