Fig. 1.

Effects of Ile, Leu and Val additions on bacitracin production. A: Effects of 40 ​mg/L Ile, Leu and Val addition at different time points on bacitracin production, respectively. B: Effects of different concentrations of Ile and Leu additions at 18 ​h on bacitracin production, respectively. Each experiment was repeated at least three times, and data are represented as the means of three replicates and bars represent the standard deviations, ∗, P ​< ​0.05; and ∗∗, P ​< ​0.01 indicate the significance levels between recombinant strains and control strain.