Enhancing the enzymatic activity of the endochitinase by the directed evolution and its enzymatic property evaluation

► The mutant strain MECH-Y185/S226 with an improved endochitinase activity was obtained by the directed evolution. ► Amino acid residues Y185 and S226 were found to be altered in the mutant endochitinase. ► The mutant endochitinase has a higher thermal and pH stabilities. ► The mechanism of the improved enzymatic properties of the mutant enzyme was explained in detailed.