Cloning of Bacillus licheniformis Xylanase Gene and Characterization of Recombinant Enzyme

Hemicellulose is a major component of lignocellulose biomass. Complete degradation of this substrate requires several different enzymatic activities, including xylanase. We isolated a strain of Bacillus licheniformis from a hot springs environment that exhibited xylanase activity. A gene encoding a 23-kDa xylanase enzyme, Xyn11, was cloned, and the recombinant protein was expressed in an Escherichia coli host and biochemically characterized. The optimum activity of the enzyme was at pH 5-7 and 40-50°C. The enzyme was stable at temperatures up to 50°C. Against birchwood xylan, the enzyme had an apparent K m of 6.7 mg/mL and V max of 379 μmol/min/mg.