Fig. 3

Growth curves of the chassis cells with the selection plasmid in response to lead and sucrose. The optical density at 600 nm of the E. coli (pZE21-PBS) strain was measured with lead at different concentrations of 0 µM (squares), 5 µM (up triangles), 20 µM (diamonds), and 50 µM (left triangles). Sucrose was used at of a 0 g L⁻¹, b 10 g L⁻¹, and c 20 g L⁻¹. Experiments were performed in triplicate, and data represent the averages and standard deviations of the means