Fig. 1

Time profiles of 2,3-BD fermentation (a cell growth; b glycerol consumption; c 2,3-BD production; d acetoin formation). Batch fermentation was carried out at 37 °C in a 5-L bioreactor containing 2.5-L initial medium [95 g/L co-substrate; molasses to crude glycerol ratio 1.5:8 (w/w)] at 37 °C, agitation speed 350 rpm, and airflow rate 0.66 vvm