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 Km of 6.7 mg/mL and Vmax of 379 μmol/min/mg.