Comparison of anaerobic (A) α- FeO(OH), (B) β- FeO(OH) (C) Fe
and (D) ferric citrate reduction between W3-18-1 wild-type and Δ mtrC , Δ undA and Δ mtrC-undA mutants. A negative control was included, in which no bacterial cells were inoculated. Reduction of Fe(III) to Fe(II) was monitored using ferrozine at 562 nm. Data are averages for triplicates and error bars indicate standard deviation. The insets indicate significance of the dissimilarity test of adonis.