Fig. 4.

Fermentation profile of the best 2,3-BD producer strain C. glutamicum ΔaceEΔpqoΔldhAΔmdh(pEKEx2-als,aldB, _Ptuf butA) as a function of time. Fifty mL of cell suspension in 80-mL fermenter incubated with 2 % (wt/vol) glucose for 30 h at 30 °C. The air flow was 10 mL min⁻¹. Error bars are shown as standard deviation of three independent replicates. Black coloured circle, biomass as OD₆₀₀; white coloured circle pH value; red coloured triangle, 2,3-BD; blue coloured square, acetoin; brown coloured diamond glucose; green coloured circle α-ketoisovalerate; black coloured square DHA; grey coloured triangle glycerol; yellow coloured diamond l-alanine