FIGURE 6.

Microbially produced Fe(III)-containing minerals enhanced Sb(III) oxidation and immobilization (A–C), and a proposed model of the Fe-N-Sb coupling mechanism mediated by strain GW3 (D). (A) Sb(III) oxidation curves of the microbially produced Fe(III)-containing minerals. Strain GW3 was anaerobically inoculated into CDM containing 1 mM KNO₃ with or without 1 mM Fe(II). After 10 days of cultivation, the precipitate was harvested and added to fresh CDM in the presence of 100 μM Sb(III). Meanwhile, the precipitate was washed three times with PBS and then used for plate counting to detect the number of bacteria. Error bars represent standard deviations of the means from three independent experiments. (B,C) EDS analysis and SEM image of the Fe(III)-containing minerals after 10 days of cultivation under the conditions described in (A). The EDS peaks for Al, Mg, and Pt may come from aluminum alloy on the sample table and the spraying Pt treatment, which is used to increase electrical conductivity.