The invention belongs to the field of
enzyme engineering and
agricultural waste conversion, and particularly relates to a preparation method and application of a
keratinase mutant for efficiently degrading
feather feed in an acidic gastric juice environment. The method comprises the following steps: replacing
amino acid Arg247 with positive charges on the zymoprotein surface based on cotG-KERQ7 in an environment with the pH value of 4, then carrying out
rational design on the
chemical property of a KERQ7
oxygen negative
ion cave, and directly introducing acidic
amino acid, so that a mechanism that the
serine protease oxygen negative
ion cave actively dynamically adjusts the
charge density through pH-dependent
protonation is introduced, and the pH-dependent
protonation of the
serine protease oxygen negative
ion cave is changed into the pH-dependent
protonation of the
serine protease oxygen negative ion cave. According to the method, the
keratinase is used as a
raw material, the oxygen anion hole adaptive low-pH environment
mutant is obtained, the acid stability and activity of the
keratinase mutant are both improved, an efficient
mutant enzyme preparation with activity and
acid resistance remarkably improved in the low-pH environment is finally obtained, reference is provided for subsequent improvement of the application value of the keratinase in the feed industry, and the method has a wide application prospect. Wide market application prospects are realized.