Fig. 2

Fed-batch production of l-tryptophan with E. coli NT1446 pF112aroFBL_Kan on a 15 L scale (37 °C, pH 7.0, DO > 30% air saturation). A: Concentrations (unit: g L⁻¹) of cell dry weight (CDW), L-tryptophan (l-trp) and acetate. B: Oxygen content in exhaust air (unit: %) and methylglyoxal concentration (unit: mg L.⁻¹). Vertical solid black lines indicate (i) the end of the batch phase (9.83 h) and (ii) the beginning of the constant feeding phase/addition of IPTG (43.9 h). The dotted red line marks the process time for cell sampling for the parallel metabolic perturbation studies (47.9 h)