Fig. 3.

(A) Electric current density I versus elapsed time, (B) polarization curve (current density vs. potential) and (C) power density curve of MFC reactors with S. oneidensis MR‐1 WT (blue), MR‐1/YYDT‐C5 mutant (orange) and MR‐1 Δbfe strains (grey) with 20 mM sodium lactate as sole carbon source. Measurements were conducted via Linear Sweep Voltammetry, as described above. Error bars represent the standard deviation of triplicate measurements.

(D) Measured optical density at 600nm (OD₆₀₀) of anodic culture of MFC reactors utilizing S. oneidensis MR‐1 WT, MR‐1/YYDT‐C5 mutant and MR‐1 Δbfe strains with 20 mM sodium lactate as sole carbon source. Measurement was done using 1 cm cuvette (1 ml sample size).

(E) Biofilm quantification using crystal violet assay: optical density at 595 nm (OD₅₉₅) of cell‐bound crystal violet solution from anodic biofilm cells of the MFC reactors.

F. The amount of lactate consumed by each reactor. Produced metabolites were mainly acetate, with succinate and pyruvate in trace amounts (data not shown). Measurements in Figure (D), (E) and (F) were done at the end of MFC experiment (day 13). Error bars represent standard deviation of triplicate measurements. P values on top of the bars denote differences between sample pairs based on nested mixed‐factor ANOVA test followed by Tukey’s HSD post hoc test. P values showing statistically significant (P < 0.05) differences are presented in bold.