Syntrophic degradation

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 ... 

Schink B (1997) Energetics of syntrophic cooperation in methanogenic degradation. Microbiol Mol Biol Rev 61 262-280. 

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. 

Phenol is carboxylated by a defined obligate syntrophic consortinm to benzoate, which is then degraded to acetate, methane, and CO2 (Knoll and Winter 1989). 

Feigel BJ, Knackmuss H-J (1993) Syntrophic interactions during degradation of 4-aminoben-zenesulfonic acid by a two species bacterial culture. Arch Microbiol 159 124—130... 

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. 

Friedrich M., Laderer U., and Schink B. (1991) Fermentative degradation of glycolic acid by defined syntrophic cocul-tmes. Arch. Microbiol. 156, 398—404. 

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. 

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. 

For a number of reasons, a great deal of effort has been directed to the degradation of alkanoic acids acetate, propionate, and butyrate are fermentation products of carbohydrates and are metabolites of the aerobic degradation of alklanes and related compounds, while long-chain acids are produced by the hydrolysis of lipids. Studies on the degradation of alkanoic adds have been carried out using both pure cultures and syntrophic associations that have been discussed in Section 4.5.1. 

Meckenstock, R. U. (1999) Fermentative tolnene degradation in anaerobic defined syntrophic cocultures. FEMS Microbiol. Lett. 177, 67-73. 

---