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Figure 4 | Journal of Biological Engineering

Figure 4

From: “NiCo Buster”: engineering E. coli for fast and efficient capture of cobalt and nickel

Figure 4

Capture of nickel and cobalt by the “NiCo buster” strain, as measured using ICP-MS. The S61 and S29 strains were cultured for 24 hours in M63G supplemented with the appropriate antibiotic at 30°C in Petri dishes. The medium was then removed and replaced by a metal solution prepared in sterile water. After 10 min (Figure 4A) or 30 min (Figure 4B and C) of contact between the bacterial biofilms and the metallic solution, the supernatant was discarded. The biofilm was collected, acidified and mixed with rhodium as an internal standard as described in the Methods section. The metal concentration of each sample was assayed using the ICP-MS technique as described in the Methods section. A) Absolute metal capture yields, expressed as the mass of captured metal divided by the mass of the biofilm. B) Relative contribution of non-specific binding and specific internalization. Absolute metal internalization yields, expressed as the mass of captured metal after washing the cells with EDTA (broken lines) divided by the mass of captured metal without washing the cells with EDTA (plain colors) after incubation in the presence of Ni (grey) or Co (white) for the S61 strain. The values shown are the means of three independent replicates. C) Contribution of the specific internalization provided by the engineered strain. The S29 strain (dashed lines) or S61 strain (plain color) was incubated in the presence of Ni (grey) or Co (white). The values represent the amount of metals assayed inside the cells in three independent samples after treatment with EDTA.

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