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Enzyme Research
Volume 2011, Article ID 593624, 9 pages
http://dx.doi.org/10.4061/2011/593624
Research Article

Cost-Effective Production and Optimization of Alkaline Xylanase by Indigenous Bacillus mojavensis AG137 Fermented on Agricultural Waste

1Department of Microbiology, Faculty of Basic Sciences, Islamic Azad University, 16 South Makran St., Heravi Sq., Pasdaran, Tehran 19585, Iran
2Food and Drug Control Laboratory Research Centre (FDCLRC), MOH, Tehran, Iran

Received 26 April 2011; Revised 19 June 2011; Accepted 21 June 2011

Academic Editor: Alane Beatriz Vermelho

Copyright © 2011 Abbas Akhavan Sepahy 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.

Abstract

A xylanase producer Bacillus mojavensis strain, called AG137, isolated from cotton farm (Kashan-Iran). The optimal xylanase activity reached at 55C & pH 9.0. Enzyme yield was studied using a medium with different agricultural wastes as inducers. Xylanase production of about 249.308 IU/mL was achieved at pH 8 and 37C, within 48 h submerged fermentation in enzyme production medium supplemented with 2% (w/v) oat bran as an optimum carbon source. A mixture of 1% (w/v) yeast extract and 1% (w/v) tryptone as optimum nitrogen sources, agitation speed 200 rpm, and inoculum size 2% (v/v) were the optimums for maximum production. Accordingly, xylanase yield from 194.68 IU/mL under non-optimized fermentation condition enhanced to 302.466 IU/mL in optimized condition. Screened xylanase is thermostable, presenting 70% stability at 60C during 30 min. Further enzyme incubation in higher temperature caused a decrease in the residual enzyme activity, yet it retained 68%–50% of its activity after 1 hour from 45C to 55C. Besides, it is stable in pH 9 and 10, maintaining over 70% of its activity for 2 h. The enzyme also could preserve 71% and 63% of its initial activity after 3 hours of pre-incubation in the same alkaline condition. Produced xylanase therefore was introduced as an alkaline-active and stable one, displaying suitable thermostability feature, confirmed by HPLC analysis. Hence, all xylanase properties highlight its promising uses in industrial scale.