A Microbial Biorealm page on the genus Syntrophomonas wolfei
Higher order taxa
Domain; Phylum; Class; Order; family; genus; species
Bacteria; Firmicutes; Clostridia; Clostridiales; Syntrophomonadaceae; Syntrophomonas; Syntrophomonas wolfei()
Description and significance
S. wolfei is a gram-negative prokaryote because of its unique multilayered cell wall and its lack of internal membrane-bound organelles. Although some strains have been found to have sporulating-specific genes (5), it does not form spores. Gene specificity was also discovered to contribute to the dependent nature of S. wolfei to H2-using bacteria (i.e. Methanospirillum hungatei) called syntrophy. This syntrophic nature was elucidated by its inability to grow in sterile conditions, and it was separated from its syntrophic counterpart by percoll gradient centrifugation.(10) Its metabolism is anaerobic using protons as the electron acceptor opposed to O2 used in aerobic organisms. Unique to this organism's metabolism is the energy source (source of electrons; the electron donor) of saturated fatty acids of carbon length 4-8, opposed to a phototrophic source. The by product of this fatty acid degradation is methane, allowing this species classification as a methanogen.
S. wolfei is isolated from anaerobic enviroments like aquatic sediment or sewage sludge(13). The importance of this organism is in its ability to B-oxidize saturated fatty acids (butyrate to octanoate (4-8 carbons long))(11) which is utilized in bioremediation. (see ECOLOGY)
S. wolfei has a circular chromosome, with 2,936,195 nt (ncbi) consisting of 2642 genes, three of which have been discovered to be integral for the syntrophic nature of the organism and related to genes in bacteria Desulfovibrio vulgaris: DVU2103, DVU2104 and DVU2108. These three genes were believed to have been transferred horizontally from archael methanogens. Their exact functions are unknown. (3) S. wolfei encodes for 2,504 proteins. The entire genome is 82% coding with a 44.9% GC content (the Phylum Firmicutes indicates a high or low GC content)(13).
Cell structure and metabolism
S. wolfei forms a gram-negative cell wall. The existence of the peptidoglycan in the gram negative multi layer was elucidated with growth inhibition by penicillin and increased sensitivity to lysis when treated with lysozyme(11). The membrane phospholipid fatty acids (PLFAs) that predominated were the monounsaturated 16:1omega7c and 16:1omega9c and the saturated 16:0 and 14:0 which may be beneficial to the anoxic enviroment and is currently under research. It takes a slightly helical shape with two to eight flagella attached to the concave side of the cell.(9)
S. wolfei is a saturated fatty acid-beta-oxidizing anaerobe. It requires syntrophy with H2-using bacteria. It metabolizes isobutyrate through butyrate to acetate(7) to which protons are utilized as the electron sink. Common metabolites like carbohydrates, alcohols, proteinaceous materials, and other organic materials do not support growth. Many compounds are required for comparable growth to a rumen fluid: thiamine, lipoic acid, biotin, cyanocobalamin, and para-aminobenzoic acid, iron, and cobalt.(1) The preferred C4 substrate of S. wolfei was discovered via the high acyl-CoA dehydrogenase activity was high in medium with C4 than in medium with either C8 or C16. Other compounds serve the metabolic need of S. wolfei for example Poly-B-hydroxyalkanoate (PHA) serves as an energy and carbon source for S.wolfei, but is regulated differently than any known pathways(12). Also, the high CoA transferase to the non-existent CoA synthetase indicates that this species activates fatty acids by transfer of CoA (from acyl-CoA). The ability of this organism for substrate-level phosphorylation was discovered by the activities of acetate kinase and phosphotransacetylase.(4)The most rapid generation time when co-cultured was 54 h (with Desulfovibrio) and 84 h (with M. hungatei)(11).
S. wolfei is a methanogen that is syntrophic with H2-using cells. Formate is the mechanism of syntrophy which was discovered because H2 could not diffuse rapidly enough to account for the level of methane synthesis in methanogenic cell cultures. (8)
S. wolfei contributes to adhesion, which forms biofilms, with other types of cells.(6) Adhesion has also been tested toward aqueous and solid phases. (See CURRENT RESEARCH)
Since S. wolfei is such a powerful organism in breaking down saturated fatty acids 4-8 carbons long, it has been utilized for degradation of contaminants for bioremediation.
Application to Biotechnology
S. wolfei uniquely breaks down 4-8 saturated fatty acids which is utilized for bioremediation. The enzymes that allow for the degradation are acyl-CoA dehydrogenase, enoyl-CoA hydratase, L-3-hydroxyacyl-CoA dehydrogenase, and 3-ketoacyl-CoA thiolase.
The mechanisms of attachment in which anaerobic organisms partition between the aqueous and solid phases in anoxic enviroments is an important step to improving the efficiency of bioremediation. (from source 6)
Elucidation of PLFAs and other structural elements aids in the understanding of the physiology and phylogeny of syntrophic bacteria. (from source 9)
The syntrophic character of S.wolfei provides issues when attempting to utilize this organism for bioremediation. Research that eliminates this dependency for H2-using organisms is being conducted. (from source 14)
Syntrophomonas wolfei gen. nov. sp. nov., an Anaerobic, Syntrophic, Fatty Acid-Oxidizing Bacterium M. J. McInerney1,2,, M. P. Bryant1,2, R. B. Hespell1 and J. W. Costerton3
2. Sousa DZ, Smidt H, Alves MM, Stams AJ, "Syntrophomonas zehnderi sp. nov., an anaerobe that degrades long-chain fatty acids in co-culture with Methanobacterium formicicum". International journal of systematic and evolutionary microbiology. 2007 Mar;57(Pt 3):609-15.
3. Scholten, Johannes C. ; Culley, David E. ; Brockman, Fred J. ; Wu, Gang ; Zhang, Weiwen. "Evolution of the syntrophic interaction between Desulfovibrio vulgaris and Methanosarcina barkeri: involvement of an ancient horizontal gene transfer". Journal: Biochemical and Biophysical Research Communications. 2007 Jan 05. 352(1):48-54.
5. Wu C, Liu X, Dong X. "Syntrophomonas cellicola sp. nov., a spore-forming syntrophic bacterium isolated from a distilled-spirit-fermenting cellar, and assignment of Syntrophospora bryantii to Syntrophomonas bryantii comb. nov". Int J Syst Evol Microbiology. 2006 Oct;56(Pt 10):2331-5.
7. Matthies C, Schink B. "Reciprocal Isomerization of Butyrate and Isobutyrate by the Strictly Anaerobic Bacterium Strain WoG13 and Methanogenic Isobutyrate Degradation by a Defined Triculture". Appl Environ Microbiology. 1992 May;58(5):1435-1439.
8. Boone DR, Johnson RL, Liu Y. "Diffusion of the Interspecies Electron Carriers H(2) and Formate in Methanogenic Ecosystems and Its Implications in the Measurement of K(m) for H(2) or Formate Uptake". Appl Environ Microbiology. 1989 Jul;55(7):1735-1741.
9. Henson JM, McInerney MJ, Beaty PS, Nickels J, White DC. "Phospholipid Fatty Acid Composition of the Syntrophic Anaerobic Bacterium Syntrophomonas wolfei". Appl Environ Microbiology. 1988 Jun;54(6):1570-1574.
10. Beaty PS, Wofford NQ, McInerney MJ. "Separation of Syntrophomonas wolfei from Methanospirillum hungatii in Syntrophic Cocultures by Using Percoll Gradients". Appl Environ Microbiology. 1987 May;53(5):1183-1185.
11. McInerney MJ, Bryant MP, Hespell RB, Costerton JW. "Syntrophomonas wolfei gen. nov. sp. nov., an Anaerobic, Syntrophic, Fatty Acid-Oxidizing Bacterium". Appl Environ Microbiology. 1981 Apr;41(4):1029-1039.
Edited by student of Rachel Larsen and Kit Pogliano