ISSN:
1432-072X
Keywords:
3-Aminobenzoate
;
Anaerobic degradation
;
Sulfate-reducing bacterium
;
Methanogenic enrichment culture
;
3-Aminobenzoyl
;
CoA synthetase
;
3-Aminobenzoyl-CoA reduction
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract A new rod-shaped, gram-negative, non-sporing sulfate reducer, strain mAB1, was enriched and isolated from marine sediment samples with 3-aminobenzoate as sole electron and carbon source. Strain mAB1 degraded 3-aminobenzoate completely to CO2 and NH3 with stoichiometric reduction of sulfate to sulfide. Cells contained carbon monoxide dehydrogenase, cytochromes, and sulfite reductase P582. Strain mAB1 degraded also benzoate, 4-aminobenzoate, hydroxybenzoates, and some aliphatic compounds. Besides sulfates, also sulfite was reduced with 3-aminobenzoate as electron donor, but not thiosulfate, sulfur, nitrate, or fumarate. The strain grew in sulfide-reduced mineral medium supplemented with 7 vitamins. Strain mAB1 was tentatively affiliated with the genus Desulfobacterium. Experiments with dense cell supsensions showed benzoate accumulation during 3-aminobenzoate degradation under conditions of sulfate limitation or cyanide inhibition. 3-Aminobenzoate was activated to 3-aminobenzoyl-CoA by cell extracts in the presence of ATP, coenzyme A, and Mg2+. Acitivity of 3-aminobenzoyl-CoA synthetase was 16 nmol per min and mg protein, with a KM for 3-aminobenzoate lower than 50 μM. Cell extract of 3-aminobenzoate-grown cells activated also 3-hydroxybenzoate (31.7 nmol per min and mg protein) and benzoate (2.3 nmol per min and mg protein), but not 2-aminobenzoate or 4-aminobenzoate. In the presence of NADH of NADPH, 3-aminobenzoyl-CoA was further metabolized to a not yet identified reduced product. Freshwater enrichments with 3-aminobenzoate in the absence of an extenal electron acceptor led to a stable methanogenic enrichment culture consisting of three types of bacteria. 3-Aminobenzoate was degraded completely to CO2 and stoichiometric amounts of CH4, with intermediary acetate accumulation.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00245361
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