Ferrous iron oxidation by anoxygenic phototrophic bacteria

Abstract

NATURAL oxidation of ferrous to ferric iron by bacteria such as Thiobacillus ferrooxidans or Gallionella ferruginea1, or by chemical oxidation2,3 has previously been thought always to involve molecular oxygen as the electron acceptor. Anoxic photochemical reactions4–6 or a photobiological process involving two photosystems7–9 have also been discussed as mechanisms of ferrous iron oxidation. The knowledge of such processes has implications that bear on our understanding of the origin of Precambrian banded iron formations10–14. The reducing power of ferrous iron increases dramatically at pH values higher than 2–3 owing to the formation of ferric hydroxy and oxyhydroxy compounds1,2,15 (Fig. 1). The standard redox potential of Fe3+/Fe2+ (E0 = +0.77 V) is relevant only under acidic conditions. At pH 7.0, the couples Fe(OH)3/Fe2+ (E′0 = -0.236V) or Fe(OH)3 + HCO3FeCO3 (E′0 = +0.200 V) prevail, matching redox potentials measured in natural sediments9,16,17. It should thus be possible for Fe(n) around pH 7.0 to function as an electron donor for anoxygenic photosynthesis. The midpoint potential of the reaction centre in purple bacteria is around +0.45 V (ref. 18). Here we describe purple, non-sulphur bacteria that can indeed oxidize colourless Fe(u) to brown Fe(in) and reduce CO2 to cell material, implying that oxygen-independent biological iron oxidation was possible before the evolution of oxygenic photosynthesis.

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References

  1. 1

    Wood, P. M. in Bacterial Energy Transduction (ed. Anthony, C.) 183–230 (Academic, London, 1988).

    Google Scholar 

  2. 2

    Stumm, W. & Morgan, J. J. Aquatic Chemistry 2nd ed (Wiley-lnterscience, New York, 1981).

    Google Scholar 

  3. 3

    Schwertmann, U. & Cornell, R. M. Iron Oxides in the Laboratory (VCH. Weinheim. 1991).

    Google Scholar 

  4. 4

    Cairns-Smith, A. G. Nature 276, 807–808 (1978).

    ADS  CAS  Article  Google Scholar 

  5. 5

    Braterman, P. S., Cairns-Smith, A. G. & Sloper, R. W. Nature 303, 163–164 (1983).

    ADS  CAS  Article  Google Scholar 

  6. 6

    François, L. M. Nature 320, 352–354 (1986).

    ADS  Article  Google Scholar 

  7. 7

    Hartman, H. in Microbial Mats: Stromatolites (eds Cohen, Y., Castenholz, R. W. & Halvorson, H. O.) 449–453 (Liss, New York, 1984).

    Google Scholar 

  8. 8

    Walker, J. C. G. Nature 329, 710–711 (1987).

    ADS  CAS  Article  Google Scholar 

  9. 9

    Cohen, Y. in Microbial Mats (eds Cohen. Y. & Rosenberg, E.) 22–36 (Am. Soc. Microbiol., Washington, 1990).

    Google Scholar 

  10. 10

    Schopf, J. W. A. Rev. Earth Planet. Sci. 3, 213–249 (1975).

    ADS  Article  Google Scholar 

  11. 11

    Schidlowski, M. in The Early History of the Earth (ed. Windley, B. F.) 525–535 (Wiley, London, 1976).

    Google Scholar 

  12. 12

    Gole, M. J. & Klein, C. J. Geol. 89, 169–183 (1981).

    ADS  Article  Google Scholar 

  13. 13

    Beukes, N. J. & Klein, C. in The Proterozoic Biosphere (eds Schopf, J. W. & Klein, C.) 147–158 (Cambridge Univ. Press, Cambridge, 1992).

    Google Scholar 

  14. 14

    Kasting, J. F., Holland, H. D. & Kump, L. R. in The Proterozoic Biosphere (eds Schopf, J, W. & Klein, C.) 159–163 (Cambridge Univ. Press, Cambridge, 1992).

    Google Scholar 

  15. 15

    Garrels, R. M. & Christ, C. L. Solutions, Minerals and Equilibria (Harper & Row, New York, 1965).

    Google Scholar 

  16. 16

    Mackenzie, F. T. & Wollast, R. in Global Chemical Cycles and their Alterations by Man (ed. Stumm, W.) 45–59 (Dahlem Konferenzen, Berlin, 1977).

    Google Scholar 

  17. 17

    Jørgensen, B. B. in Microbial Geochemistry (ed. Krumbein, W. E.) 91–124 (Blackwell, Oxford, 1983).

    Google Scholar 

  18. 18

    Dutton, P. L. & Prince, R. C. in The Photosynthetic Bacteria (eds Clayton, R. K. & Sistrom, W. R.) 525–570 (Plenum, New York, 1978).

    Google Scholar 

  19. 19

    Widdel, F. & Bak, F. in The Prokaryotes Vol. 4 (eds Balows, A., Trüper, H. G., Dworkin, M., Harder, W. & Schleifer, K.-H.) 3352–3378 (Springer. New York, 1992).

    Google Scholar 

  20. 20

    Pfennig, N. Int. J. syst. Bact. 28, 283–288 (1978).

    CAS  Article  Google Scholar 

  21. 21

    Cohen, Y., Jørgensen, B. B., Revsbech, N. P. & Poplawski, R. Appl. environ. Microbiol 51, 398–407 (1986).

    CAS  PubMed  PubMed Central  Google Scholar 

  22. 22

    Pfennig, N. in Bergey's Manual of Systematic Bacteriology Vol. 3 (eds Staley, J. T., Bryant, M. P., Pfennig, N. & Holt, J. G.) 1650–1651 (Williams & Wilkins. Baltimore, 1989).

    Google Scholar 

  23. 23

    Lovley, D. R. Microbiol. Rev. 55, 259–287 (1991).

    CAS  PubMed  PubMed Central  Google Scholar 

  24. 24

    Nealson, K. H. & Myers, C. R. Appl. environ. Microbiol. 58, 439–443 (1992).

    CAS  PubMed  PubMed Central  Google Scholar 

  25. 25

    Stookey, L. L. Analyt. Chem. 42, 779–781 (1970).

    CAS  Article  Google Scholar 

  26. 26

    Lovley, D. R. & Philipps, E. J. P. Appl. environ. Microbiol. 51, 683–689 (1986).

    CAS  PubMed  PubMed Central  Google Scholar 

  27. 27

    Lowry, O. H., Rosebrough, N. J., Farr, A. L. & Randall, R. J. J. biol. Chem. 193, 265–275 (1951).

    CAS  PubMed  Google Scholar 

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Widdel, F., Schnell, S., Heising, S. et al. Ferrous iron oxidation by anoxygenic phototrophic bacteria. Nature 362, 834–836 (1993). https://doi.org/10.1038/362834a0

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