Fig. 3

Effect of metabolic coupling strategy on l-methionine production. A Coupling of the central carbon metabolism module to the l-methionine terminal synthetic module by deleting the succinyl-CoA synthetase sucCD. B Coupling of the central carbon metabolism module with the l-methionine terminal synthetic module by deleting the pykF and pykA genes. C l-Methionine and l-isoleucine production and OD₆₀₀ of MET10, MET11, MET12, and MET13. Data are presented as the mean values with the standard deviation from three biological replicates. One-way analysis of variance (ANOVA) was used to determine significant differences (* p < 0.05, ** p < 0.01)