Acetogenic Bacteria

Frank Imkamp, Johann Wolfgang Goethe University, Frankfurt, Germany
Volker Müller, Johann Wolfgang Goethe University, Frankfurt, Germany

Published online: January 2007

DOI: 10.1002/9780470015902.a0020086

Acetogenic bacteria are a specialized group of strictly anaerobic bacteria that are ubiquitous in nature and essential for the global carbon cycle. Acetogens are characterized by a unique pathway, the Wood–Ljungdahl pathway of carbon dioxide reduction with the acetyl-CoA synthase as the key enzyme of the pathway.

Keywords: acetogens; anaerobic respiration; acetyl; CoA pathway; bioenergetics; anaerobic ecology

Figure 1. Fermentation of hexoses to acetate by acetogenic bacteria. The fermentation yields only acetate according to eq. [III]. This fermentation is referred to as homoacetogenesis.
Figure 2. The Wood–Ljungdahl pathway. Abbreviations: THF, tetrahydrofolate; HSCoA, coenzyme A; Pi, inorganic phosphate; e–, electron; CoFe/S-P, corrinoid-iron sulfur protein; ATP, adenosine 5¢-triphosphate.
Figure 3. Chemiosmotic mechanisms by which acetogens conserve energy. (A) Protondependent conservation of energy with the hypothetical involvement of different oxidoreductases that activate reducing equivalents for electron transport. (B)  Na+ dependent conservation of energy; the  Na+ gradient may be generated by one of the methyl transfer reactions leading to a methylated ACS.
Figure 4. Aromatic substrates that are utilized by acetogens.
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 References
    Dangel W, Schulz H, Diekert G, König H and Fuchs G (1987) Occurrence of corrinoid containing membrane proteins in anaerobic bacteria. Archives of Microbiology 148: 52–56.
    Drake HL, Küsel K and Matthies C (2002) Ecological consequences of the phylogenetic and physiological diversities of acetogens. Antonie van Leeuwenhoek 81: 203–213.
    Fuchs G (1986) CO2 fixation in acetogenic bacteria: variations on a theme. FEMS Microbiology Reviews 39: 181–213.
    Gottschalk G and Thauer RK (2001) The  Na+-translocating methyltransferase complex from methanogenic archaea. Biochimica et Biophysica Acta 1505: 28–36.
    Grahame DA (2003) Acetate C-C bond formation and decomposition in the anaerobic world: the structure of a central enzyme and its key active-site metal cluster. Trends in Biochemical Sciences 28: 221–224.
    Heise R, Müller V and Gottschak G (1989) Sodium dependence of acetate formation by the acetogenic bacterium Acetobacterium woodii. Journal of Bacteriology 171: 5473–5478.
    Imkamp F and Müller V (2002) Chemiosmotic energy conservation with  Na+ as the coupling ion during hydrogen-dependent caffeate reduction by Acetobacterium woodii. Journal of Bacteriology 184: 1947–1951.
    Ivey DM and Ljungdahl LG (1986) Purification and characterization of the F1-ATPase from Clostridium thermoaceticum. Journal of Bacteriology 165: 252–257.
    Küsel K and Drake HL (1995) Effects of environmental parameters on the formation and turnover of acetate by forest soils. Applied and Environmental Microbiology 61: 3667–3675.
    Müller V, Aufurth S and Rahlfs S (2001) The  Na+ cycle in Acetobacterium woodii: identification and characterization of a  Na+ translocating F1F0-ATPase with a mixed oligomer of 8 and 16 kDa proteolipids. Biochimica et Biophysica Acta 1505: 108–120.
    Ragsdale SW (1991) Enzymology of the acetyl-CoA pathway of autotrophic CO2 fixation. CRC Critical Reviews Biochemistry and Molecular Biology 26: 261–300.
 Further Reading
    book Drake HL, Küsel K and Matthies C (2004) "Acetogenic prokaryotes". In: Dworkin M, Falkow S, Rosenberg E, Schleifer K-H, and Stackebrandt E (eds) The Prokaryotes, 3rd edn. New York: Springer.
    book Müller V, Imkamp F, Rauwolf A, Küsel K and Drake HL (2004) "Molecular and cellular biology of acetogenic bacteria". In: Nakano MM and Zuber P (eds), pp. 251–281. Strict and Facultative Anaerobes; Medical and Environmental Aspects. Norfolk, UK: Horizon Press
    Müller V (2003) Energy conservation in acetogenic bacteria. Applied and Environmental Microbiology. 69: 6345–6353.
    book Wood HG and Ljungdahl LG (1991) "Autotrophic Character of the Acetogenic Bacteria". In: Shively JM and Barton LL (eds), pp. 201–250. Variations in Autotrophic Life. San Diego: Academic Press

Related Sub-Topics:

Bacteria | Energetics and Catabolism | Lithotrophy
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Article Title: Acetogenic Bacteria
 
How to Cite close
Imkamp, Frank, and Müller, Volker(Jan 2007) Acetogenic Bacteria. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0020086]