Expression of PDR in E. coli C41 in TB ( ▲ ) and minimal ( □ ) media in the presence of 0.2 mg/mL Ferric citrate, 2 mM cysteine, 0.2 mg/ml FeSO4 and 100 mg/L carbenicillin. Starter cultures were grown in LB overnight at 37 °C, 250 rpm in the presence of carbenicillin, but without iron-sulfur additives. Starter cultures (0.5 mL) were used to inoculate 50 ml of media in 0.25 L conical flasks for both TB and minimal media flasks. Cultures were grown at 26 °C, 200 rpm. PDR expression was induced by adding 0.5 mM IPTG at time zero. Changes in the apparent absorbance at 600 nm (A), pH (B) and enzyme expression in cell culture (C) were evaluated by enzymatic assays as described in Material and Methods.