Fig. 6

Fed-batch fermentation profiles of B. licheniformis mutant WX-02ΔgdhΔacoR in a bench top (5-L) fermenter with pH control. The tank was stirred at 350 rpm with 3-L/min aeration for first 16 h, and then decreased to 200 rpm and 1.5 mL/min for the remaining period. Glucose was fed to the medium from 24–70 h to maintain the residual glucose concentration between 10–20 g/L. Filled square Biomass; filled circle residual glucose; filled triangle meso-2,3-BD; ❊, Acetoin; ☆, Lactic acid; circle acetic acid; square ethanol. The arrow indicates the start of feeding the reactor with a concentrated glucose solution (650 g/L)