Improved thermal performance of Thermomyces lanuginosus GH11 xylanase by engineering of an N-terminal disulfide bridge

► An N-terminal disulfide bridge stabilized a thermophilic xylanase by about 10 °C. ► The upper limit for the performance of the mutant enzyme at pH 8-9 was about 75 °C. ► The presence of substrate decreased slightly the thermostability at alkaline pH. ► The latter effect did not counteract the benefit conferred by the disulfide bridge.