Isolation and Identification of Xylanolytic Enzyme from an Effective Strain Bacillus Licheniformis Isolated from the Decaying Wood.

ABSTRACT

A new species of Bacillus licheniformis produced extracellular xylanase under submerged fermentation when wheat bran is used as carbon source. The xylan is the most common hemicellulosic polysaccharide in food industry and agricultural wastes, comprising a backbone of xylose residues linked by β-1,4 glycosidic bonds. Bacillus licheniformis has been shown to be a promising organism for enhanced production of xylanases & β-xylosidase under submerged fermentation (SmF). The optimization of cultural conditions and carbon, nitrogen sources for enzymes production. The bacterial strain Bacillus licheniformis was cultivated using as substrate xylan, wheat bran, corn straw, corncob, and sugarcane bagasse. Wheat bran has been a good xylanase (16.8U/ml) & β xylosidase (5.6U/ml) activity after 48h of fermentation. Maximum enzyme activity was observed in xylan as carbon source and peptone as nitrogen source. Both crude enzymes were characterized and a bacterial xylanase shows optimum pH for xylanase activity at 6.5 & β xylosidase were found to be 6.0. The optimum temperatures were 450C for both and they were thermally stable up to 500C. The parameters of Vmax and Km obtained using Line weaver-Burk plot method were 277.7μmol / min/mg and 5.26 mg /L correspondingly.