Archives of Microbiology

, Volume 150, Issue 2, pp 131–137

The role of auxiliary oxidants in maintaining redox balance during phototrophic growth of Rhodobacter capsulatus on propionate or butyrate

  • David J. Richardson
  • Glenn F. King
  • David J. Kelly
  • Alastair G. McEwan
  • Stuart J. Ferguson
  • J. Barry Jackson
Original Papers


Phototrophic growth of Rhodobacter capsulatus (formerly Rhodopseudomonas capsulata) under anaerobic conditions with either butyrate or propionate as carbonsource was dependent on the presence of either CO2 or an auxiliary oxidant. NO-3, N2O, trimethylamine-N-oxide (TMAO) or dimethylsulphoxide (DMSO) were effective provided the appropriate anaerobic respiratory pathway was present. NO-3was reduced extensively to NO-3, TMAO to trimethylamine and DMSO to dimethylsulphide under these conditions. Analysis of culture fluids by nuclear magnetic resonance showed that two moles of TMAO or DMSO were reduced per mole of butyrate utilized and one mole of either oxidant was reduced per mole of propionate consumed. The growth rate of Rb. capsulatus on succinate or malate as carbon source was enhanced by TMAO in cultures at low light intensity but not at high light intensities. A new function for anaerobic respiration during photosynthesis is proposed: it permits reducing equivalents from reduced substrates to pass to auxiliary oxidants present in the medium. The use of CO2 or auxiliary oxidants under phototrophic conditions may be influence by the availability of energy from light. It is suggested that the nuclear magnetic resonance methodology developed could have further applications in studies of bacterial physiology.

Key words

Photosynthetic bacteria (Rhodobacter capsulatusPhototrophic growth Nitrate reduction TMAO reduction Redox balance NMR assay 











nuclear magnetic resonance


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Albers A, Gottschalk G (1976) Acetate metabolism in Rhodopseudomonas gelatinosa and several other Rhodospirillaceae. Arch Microbiol 111:45–49Google Scholar
  2. Alef K, Jackson JB, McEwan AG, Ferguson SJ (1985) The activities of two pathways of nitrate reduction in Rhodopseudomonas capsulata. Arch Microbiol 142:403–408Google Scholar
  3. Coleman JK, Cornish-Bowden A, Cole JA (1978) Purification and properties of nitrite reductase from Escherichia coli K12. Biochem J 175:483–493Google Scholar
  4. Crofts AR, Wraight CA (1883) The electrochemical domain of photosynthesis. Biochim Biophys Acta 726:149–185Google Scholar
  5. Farrar TC, Becker ED (1971) Pulse and fourier transform NMR: introduction to theory and methods. Academic Press, New YorkGoogle Scholar
  6. Ferguson SJ, Jackson JB, McEwan AG (1987) Anaerobic respiration in the Rhodospirillaceae: characterisation of pathways and evaluation of roles in redox balancing during photosynthesis. FEMS Microbiol Revs 46:117:143Google Scholar
  7. Kelly DJ, Richardson DJ, Ferguson SJ, Jackson JB (1988) Isolation of Tn5 insertion mutants of Rhodobacter capsulatus unable to reduce trimethylamine-N-oxide and dimethylsulphoxide. Arch Microbiol 150:138–144Google Scholar
  8. King GF, Richardson DJ, Jackson JB, Ferguson SJ (1987) Dimethylsulphoxide and trimethylamine-N-oxide as electron transport acceptors: use of nuclear magnetic resonance to assay and characterise the reductase system in Rhodobacter capsulatus. Arch Microbiol 149:47–51Google Scholar
  9. Kornberg HL, Lascelles J (1960) The formation of isocitratase by the Athiorhodaceae. J Gen Microbiol 23:511–517Google Scholar
  10. Lascelles J (1960) The formation of ribulose-1,5-diphosphate carboxylase by growing cultures of Athiorhodaceae. J Gen Microbiol 23:499–510Google Scholar
  11. McEwan AG, George CL, Ferguson SJ, Jackson JB (1982) A nitrate reductase activity in Rhodopseudomonas capsulata linked to electron transfer and generation of a membrane protential. FEBS Lett 150:277–280Google Scholar
  12. McEwan, Ferguson SJ, Jackson JB (1983) Electron flow to dimethylamine-N-oxide generates a membrane potential in Rhodopseudomonas capsulata. Arch Microbiol 136:300–305Google Scholar
  13. McEwan AG, Jackson JB, Ferguson SJ (1984) Rationalisation of properties of nitrate reductases in Rhodopseudomonas capsulata. Arch Microbiol 137:333–349Google Scholar
  14. McEwan AG, Wetzstein HG, Ferguson SJ, Jackson JB (1985a) Periplasmic location of the terminal reductase in trimethylamine-N-oxide and dimethylsulphoxide respiration in the photosynthetic bacterium Rhodopseudomonas capsulata. Biochim Biophys Acta 806:810–417Google Scholar
  15. McEwan AG, Greenfield AJ, Wetzstein HG, Jackson JB, Ferguson SJ (1985b), Nitrous oxide reduction by members of the family Rhodospirillaceae and the nitrous oxide reductase of Rhodopseudomonas capsulata. J Bacteriol 164:823–830Google Scholar
  16. McEwan AG, Cotton NPJ, Ferguson SJ, Jackson JB (1985c) The role of auxiliary oxidents in the maintenance of a balanced redox poise for photosynthesis in bacteria. Biochim Biophys Acta 810:140–147Google Scholar
  17. Metzler DE (1977) Biochemistry: the chemical reactions of living cells. Academic Press, New York, p 1129Google Scholar
  18. Ormerod JG (1956) The use of radioactice carbon dioxide in the measurements of carbon dioxide fixation in Rhodospirillum rubrum. Biochem J 64:373–380Google Scholar
  19. Richardson DJ, Kelly DJ, Jackson JB, Ferguson SJ, Alef K (1986) Inhibitory effects of myxothiazol and 2-n-heptyl-4-hydroxyquinone-N-oxide on the auxiliary electron transport pathways of Rhodobacter capsulatus. Arch Microbiol 146:159–165Google Scholar
  20. Schultz JE, Weaver PF (1982) Fermentation and anaerobic respiration by Rhodospirillum rubrum and Rhodopseudomonas capsulata. J Bacteriol 149:181–190Google Scholar
  21. Van Niel CB (1944) The culture, general physiology, morphology and classification of the non-sulphur purple and non-bacteria. Bacteriol Rev 8:1–118Google Scholar
  22. Weaver PF, Wall JD, Gest H (1975) Characterisation of Rhodopseudomonas capsulata. Arch Microbiol 105:207–216Google Scholar

Copyright information

© Springer-Verlag 1988

Authors and Affiliations

  • David J. Richardson
    • 1
  • Glenn F. King
    • 2
  • David J. Kelly
    • 1
  • Alastair G. McEwan
    • 1
  • Stuart J. Ferguson
    • 2
  • J. Barry Jackson
    • 1
  1. 1.Department of BiochemistryUniversity of BirminghamBirminghamUK
  2. 2.Department of BiochemistryUniversity of OxfordOxfordUK
  3. 3.Department of MicrobiologyUniversity of SheffieldSheffieldUK

Personalised recommendations