Optimization of fermentation medium of methionine γ-lyase by using response surface methodology

Objective:In order to obtain low-cost and high-activity industrial medium,the fermentation medium of methionine γ-lyase(MGL)was optimized. Method:The factors influencing the enzyme activity were determined by single factor experiment,The factors influencing the activity of the enzyme were investigated by Plackett-Burman design.The result showed that the concentration of glycerol,Angel yeast,zhilong yeast played important roles in influencing the content of MGL.The most significant conditions were determined by the steepest climbing experiment and Box-Behnken response surface design. Result:The results showed that the activity of MGL reached 11.30 U/mL when the concentration of glycerol was 1.40%,Angel yeast was 0.80% and zhilong yeast was 0.96%. After fermentation verification,the activity of MGL was(11.06±0.15) U/mL,which was 5.69 times higher than LB medium 1.65 U/mL,showing a good optimization effect. Conclusion:The optimal proliferation medium was as follows:glycerol 1.40%,Angel yeast 0.80%,zhilong yeast 0.96%,lactose 1.20%,Angel peptone 1.80%,NaCl 0.90%,K₂HPO₄ 1.80%,MgSO₄ 0.20%.