Fig. 2.

Production of d-lactate by batch fermentation. The engineered strain was cultured in a bench fermenter containing crude glycerol. The batch fermentation was under the control of the DO to proceed the aerobic growth phase and the fermentative production phase. The fermentation was initiated with the cell density at OD₅₅₀ of 1. The absorbance measurement for the cell density in the production phase was interfered with crude glycerol and Ca(OH)₂ and, therefore, not reported. The experiment was duplicated. The typical fermentation profiles were reported for strain EcoB-140 (a) and strain EcoB-140B (b). Cell density (black circle); crude glycerol (black up-pointing triangle); d-lactate (black square); acetate (X)