General Microbiology - Schlegel, H. 1987

Electron transport under anaerobic conditions
Reduction of Fe (III) ions to Fe (II)

Mixed populations of soil Bacteria reduce Fe (III) ions to Fe (II) under anaerobic conditions. If nitrate and nitrite ions are also present in the medium alongside Fe (III), they are reduced first (to nitrite and N2, denitrification), and only thereafter are Fe (III) ions reduced. It is suggested that electron transfer to trivalent iron is carried out by nitrate reductase A. Since nitrate reduction is coupled with Oxidative Phosphorylation, it is also possible that Fe (III) reduction can be utilized in The process of "Anaerobic Respiration." The redox potential, which is +770 mV for the Fe3+/Fe2+ couple, makes such a reaction thermodynamically feasible. Since trivalent iron oxides are virtually insoluble in Water, they must first be converted into a soluble form capable of penetrating bacterial Cells. This is likely accomplished via siderophores. Unsurprisingly, under such conditions, only slow and negligible bacterial growth is observed.



Last update: 13/08/2026

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