Rational Design to Improve the Thermostability of Cutinase for Aqueous-Phase Synthesis of Flavor Ester

In order to improve the thermal stability of cutinase AFLACUT-2, the mutants were predicted and screened based on the change of free energy (ΔΔG) for protein folding, and the enzymatic properties of the selected mutant were characterized. The results showed that the thermal stability of mutant Q163M was significantly improved without affecting the enzymatic activity, which retained 86.09% of its activity when incubated at 40 ℃ for 168 h, compared with that of the wild-type strain. At 60 ℃, the half-life of the mutant was 1.68 times higher than that of the wild-type strain. In addition, compared with the wild-type strain, mutant Q163M showed better tolerance to an acidic environment. The mechanism for improved thermal stability of mutant Q163M was elucidated by intermolecular forces and molecular dynamic simulation. These results provide a basis for rationally modifying the thermal stability of cutinase and improving its capacity for the aqueous-phase synthesis of flavor ester at high temperature.