Metabolic flux distribution in E. coli MG1655 single knockout strains Δ arcA and Δ iclR , and the double knockout strain Δ arcA Δ iclR cultivated in glucose abundant (batch) and glucose limiting (continuous) conditions. The ratios, shown in Figure 4, were used as constraints to determine net fluxes. From top to bottom, values represent fluxes of the wild type, the ΔarcA and ΔiclR strain, and the ΔarcAΔiclR strain. Standard errors are calculated by propagating measured errors of extracellular fluxes and ratios. Absolute fluxes in were rescaled to the glucose uptake rate (shown in the upper boxes) to allow a clear comparison in flux distribution between the different strains.