Abstract
A mutant of Methanosarcina barkeri (Fusaro) is able to grow on pyruvate as the sole carbon and energy source. During growth, pyruvate is converted to CH4 and CO2, and about 1.5 mol of ATP per mol of CH4 is formed (A.-K. Bock, A. Prieger-Kraft, and P. Schönheit, Arch. Microbiol. 161:33-46, 1994). The pyruvate-utilizing mutant of M. barkeri could also grow on pyruvate when methanogenesis was completely inhibited by bromoethanesulfonate (BES). The mutant grew on pyruvate (80 mM) in the presence of 2 mM BES with a doubling time of about 30 h up to cell densities of about 400 mg (dry weight) of cells per liter. During growth on pyruvate, the major fermentation products were acetate and CO2 (about 0.9 mol each per mol of pyruvate). Small amounts of acetoin, acetolactate, alanine, leucine, isoleucine, and valine were also detected. CH4 was not formed. The molar growth yield (Yacetate) was about 9 g of cells (dry weight) per mol of acetate, indicating an ATP yield of about 1 mol/mol of acetate formed. Growth on pyruvate in the presence of BES was limited; after six to eight generations, the doubling times increased and the final cell densities decreased. After 9 to 11 generations, growth stopped completely. In the presence of BES, suspensions of pyruvate-grown cells fermented pyruvate to acetate, CO2, and H2. CH4 was not formed. Conversion of pyruvate to acetate, in the complete absence of methanogenesis, was coupled to ATP synthesis. Dicyclohexylcarbodiimide, an inhibitor of H(+)-translocating ATP synthase, did not inhibit ATP formation. In the presence of dicyclohexylcarbodiimide, stoichiometries of up to 0.9 mol of ATP per mol of acetate were observed. The uncoupler arsenate completely inhibited ATP synthesis, while the rates of acetate, CO2, and H2 formation were stimulated up to fourfold. Cell extracts of M. barkeri grown on pyruvate under nonmethenogenic conditions contained pyruvate: ferredoxin oxidoreductase (0.5 U/mg), phosphate acetyltransferase (12 U/mg), and acetate kinase (12 U/mg). From these data it is concluded that ATP was synthesized by substrate level phosphorylation during growth of the M. barkeri mutant on pyruvate in the absence of methanogenesis. This is the first report of growth of a methanogen under nonmethanogenic conditions at the expense of a fermentative energy metabolism.
Full Text
The Full Text of this article is available as a PDF (224.2 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Balch W. E., Fox G. E., Magrum L. J., Woese C. R., Wolfe R. S. Methanogens: reevaluation of a unique biological group. Microbiol Rev. 1979 Jun;43(2):260–296. doi: 10.1128/mr.43.2.260-296.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Blaut M., Gottschalk G. Coupling of ATP synthesis and methane formation from methanol and molecular hydrogen in Methanosarcina barkeri. Eur J Biochem. 1984 May 15;141(1):217–222. doi: 10.1111/j.1432-1033.1984.tb08178.x. [DOI] [PubMed] [Google Scholar]
- Bode C., Goebell H., Stähler E. Zur Eliminierung von Trübungsfehlern bei der Eiweissbestimmung mit der Biuretmethode. Z Klin Chem Klin Biochem. 1968 Sep;6(5):418–422. [PubMed] [Google Scholar]
- Decker K., Jungermann K., Thauer R. K. Energy production in anaerobic organisms. Angew Chem Int Ed Engl. 1970 Feb;9(2):138–158. doi: 10.1002/anie.197001381. [DOI] [PubMed] [Google Scholar]
- DiMarco A. A., Bobik T. A., Wolfe R. S. Unusual coenzymes of methanogenesis. Annu Rev Biochem. 1990;59:355–394. doi: 10.1146/annurev.bi.59.070190.002035. [DOI] [PubMed] [Google Scholar]
- Ellermann J., Hedderich R., Böcher R., Thauer R. K. The final step in methane formation. Investigations with highly purified methyl-CoM reductase (component C) from Methanobacterium thermoautotrophicum (strain Marburg). Eur J Biochem. 1988 Mar 15;172(3):669–677. doi: 10.1111/j.1432-1033.1988.tb13941.x. [DOI] [PubMed] [Google Scholar]
- Ferry J. G. Methane from acetate. J Bacteriol. 1992 Sep;174(17):5489–5495. doi: 10.1128/jb.174.17.5489-5495.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Inatomi K., Maeda M., Futai M. Dicyclohexylcarbodiimide-binding protein is a subunit of the Methanosarcina barkeri ATPase complex. Biochem Biophys Res Commun. 1989 Aug 15;162(3):1585–1590. doi: 10.1016/0006-291x(89)90856-5. [DOI] [PubMed] [Google Scholar]
- Jones W. J., Nagle D. P., Jr, Whitman W. B. Methanogens and the diversity of archaebacteria. Microbiol Rev. 1987 Mar;51(1):135–177. doi: 10.1128/mr.51.1.135-177.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kaesler B., Schönheit P. Methanogenesis and ATP synthesis in methanogenic bacteria at low electrochemical proton potentials. An explanation for the apparent uncoupler insensitivity of ATP synthesis. Eur J Biochem. 1988 May 16;174(1):189–197. doi: 10.1111/j.1432-1033.1988.tb14081.x. [DOI] [PubMed] [Google Scholar]
- Schönheit P., Wäscher C., Thauer R. K. A rapid procedure for the purification of ferredoxin from Clostridia using polyethyleneimine. FEBS Lett. 1978 May 15;89(2):219–222. doi: 10.1016/0014-5793(78)80221-x. [DOI] [PubMed] [Google Scholar]
- Thauer R. K., Möller-Zinkhan D., Spormann A. M. Biochemistry of acetate catabolism in anaerobic chemotrophic bacteria. Annu Rev Microbiol. 1989;43:43–67. doi: 10.1146/annurev.mi.43.100189.000355. [DOI] [PubMed] [Google Scholar]