MODIFICATION OF XYLANASE FOR IMPROVING THERMOPHILE, ALKALOPHILICITY AND THERMAL STABILITY

摘要

PROBLEM TO BE SOLVED: To produce a xylanase enzyme excellent in performance on the bleaching of pulp, and more concretely to provide a modified 11 group xylanase exhibiting improved thermophilic, alkalophilic and thermally stable properties in comparison with natural xylanase. SOLUTION: This modified xylanase is (1) a xylanase obtained by changing the 10, 27 and 29 amino acids of Trichoderma reesei xylanase II or the corresponding amino acids of another 11 group xylanase with histidine, methionine and leucine, or (2) a xylanase obtained by substituting the amino acid of the N-terminal region by an amino acid originated from another xylanase enzyme. In a preferable embodiment, a short amino acid sequence originated from Trichoderma fusca xylanase is substituted by natural Bacillus circulans xylanase or Trichoderma reesei xylanase to form a chimera xylanase having high thermophilic and alkalophilic properties.