Syntrophic anaerobic

Wallrabenstein C, E Hauschild, B Schink (1995) Syntrophobacter pfennigii sp. nov., new syntrophically propionate-oxidizing anaerobe growing in pure culture with propionate and sulfate. Arch Microbiol 164 346-352. 

Stable metabolic associations generally between pairs of anaerobic bacteria have been termed syntrophs, and these are effective in degrading a number of aliphatic carboxylic acids or benzoate under anaerobic conditions. These reactions have been discussed in reviews (Schink 1991, 1997 Lowe et al. 1993) that provide lucid accounts of the role of syntrophs in the degradation of complex organic matter. Two examples are given here to illustrate the experimental intricacy of the problems besetting the study of syntrophic metabolism under anaerobic conditions ... 

Mclnerney Ml, MP Bryant, RB Hespell, JW Costerton (1981) Syntrophomonas wolfei gen. nov., sp. nov., an anaerobic, syntrophic, fatty acid-oxidizing bacterium. Appl Environ Microbiol 41 1029-1039. 

Stieb M, B Schink (1985) Anaerobic oxidation of fatty acids by Clostridium bryantii sp. nov., a sporeforming, obligately syntrophic bacterium. Arch Microbiol 140 387-390. 

The procedure is particularly suited to the study of anaerobic transformations since there are no problems resulting from problems with oxygen limitation. A good example is provided by the application of C NMR to the intricate relations of fumarate, succinate, propionate, and acetate in a syntrophic organism both in the presence (Houwen et al. 1991), and in the absence of methanogens (Plugge et al. 1993 Stams et al. 1993). 

In summary, the anaerobic degradation of alkanoic acids may truly be described as ubiquitous and is carried out by organisms with widely different taxonomic affinity both in pure culture and in syntrophic associations. 

They occur in anaerobic sediments rich in sulfide and elemental sulfur, and live syntrophically with the phototrophic green sulfur bacteria (Chlorobi-aceae) that photooxidize H2S to S and excrete sulfur extracellularly. Desulfuromonas regenerate H2S by sulfur respiration, using, at least in part, organic matter leaked by Chlombium cells. 

Jackson, B. E., Bhupathiraju, V. K., Tanner, R. S., Woese, C. R., and Mclnemey, M. J., 1999, Syntrophus aciditrophicus sp. nov., A new anaerobic bacterium that degrades fatty acids and benzoate in syntrophic association with hydrogen-using microorganisms [In Process Citation], Arch. Microbial. 171(2) 107914. 

FDHs were isolated from another type of anaerobic bacterium (Eubacterium acidacminophilum) FDHs catalyze the reversible reduction of CO2 to formate (Table 2), with the concomitant transfer of two electrons from the appropriate electron carrier. This reaction has a very negative reduction potential (-420 mV, SHE). The syntrophic bacterium Syntrophobacter fumaroxidans constitutively expressed two W-containing FDH s (FDH-1 and FDH-2) when grown on fumarate or propionate. The purified enzymes exhibit high formate-oxidation and CO2-reduction rates and very low Km values for formate. 

A second possibility yields the same net reaction but is driven by a syntrophic relationship between an organism that oxidizes CH4 to CO2/H2 and an S04 -reducing bacterium that consumes H2, thereby maintaining a thermodynamically favorable environment for the reaction (Hoehler et al., 1994). In this case, anaerobic CH4 oxidation is analogous to hydrogenotrophic methanogenesis in... 

Cord-Ruwisch R., Lovley D. R., and Schink B. (1998) Growth of Geobacter sulfurreducens with acetate in syntrophic cooperation with hydrogen-oxidizing anaerobic partners. Appl. Environ. Microbiol. 64, 2232-2236. 

KnoU G. and Winter J. (1989) Degradation of phenol via carboxylation to benzoate by a defined, obligate syntrophic consortium of anaerobic bacteria. Appl. Microbiol. Biotech. 30, 318-324. 

Mclnerney M. J., Bryant M. P., and Pfennig N. (1979) Anaerobic bacterium that degrades fatty acids in syntrophic association with methanogens. Arch. Microbiol. 122, 129-135. 

Thiele J. H. and Zeikus J. G. (1988) Control of interspecies electron flow during anaerobic digestion significance of formate transfer versus hydrogen transfer during syntrophic... 

Oxidation under anaerobic conditions of long-chain aliphatic carboxylic acids was established in syntrophic cultures of Clostridium bryantii / Desulfovibrio sp. (Stieb and Schink 1985), Syntrophomonas sapovorans /Methanospirillum hungatei (Roy et al. 1986), and S. wolfei in coculture with H2-utilizing anaerobic bacteria (Mclnerney et al. 

There has been considerable interest in the anaerobic degradation of propionate that is a fermentation product of many complex substrates, and syntrophic associations of acetogenic and metha-nogenic bacteria have been obtained. 

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