Cultivation medium and conditions

Luria–Bertani (LB) medium containing NaCl 10 g/L, tryptone 10 g/L and yeast extract 5 g/L were used for cultivation of C. glutamicumand E. coli . Antibiotic was added to the medium for mutants screening when needed: 50 μg/mL kanamycin or 30 μg/mL chloramphenicol for E. coli , 10 μg/mL kanamycin or 15 μg/mL chloramphenicol forC. glutamicum .
For the shaking flask fermentation experiment, the correct monoclonal strains were activated twice on the LB medium for 36 h, and then the appropriate amount of bacterial seed was inoculated into a 100 mL flask containing 10 mL of seed solution. The seed medium contains glucose 30 g/L, corn steep liquor 10 g/L, yeast extract 10 g/L, (NH4)2SO4 15 g/L, MgSO4 2.5 g/L, KH2PO4 1 g/L, K2HPO4 0.5 g/L, Na2HPO4·12H2O 1.26 g/L and CaCO3 10 g/L, the pH was adjusted to 6.7 (Supplementary Information: Figure S1). The monoclonal strains were incubated at 30°C, 220 rpm for 11 h. Take an appropriate amount of seed solution and inoculate it in a 250 mL Erlenmeyer flask containing 20 mL of fermentation medium so that the OD600 of the initial fermentation solution is 1 at 600 nm. The fermentation medium contains xylose 100 g/L or glucose 70 g/L and xylose 30 g/L, yeast extract 6 g/L, (NH4)2SO4 50 g/L, MgSO4 2.5 g/L, KH2PO4 1 g/L, K2HPO4 0.5 g/L, Na2HPO4·12H2O 1.26 g/L, MnSO4·H2O 0.02 g/L, FeSO4·7H2O 0.02 g/L, biotin 0.9 μM, thiamine-HCl 15 μM and CaCO3 10 g/L, while the pH was adjusted to 6.7. The strains in fermentation medium were incubated at 31.5°C, 250 rpm for 72 h.