Abstract
We cloned and purified the major family 10 xylanase (Xyn10A) from Acidothermus cellulolyticus 11B. Xyn10A was active on oat spelt and birchwood xylans between 60°C and 100°C and between pH 4 and pH 8. The optimal activity was at 90°C and pH 6; specific activity and K(m) for oat spelt xylan were 350 μmol xylose produced min⁻¹ mg of protein⁻¹ and 0.53 mg ml⁻¹, respectively. Based on xylan cleavage patterns, Xyn10A is an endoxylanase, and its half-life at 90°C was approximately 1.5 h in the presence of xylan.