Characterization of Aquamicrobium defluvii gen. nov. sp. nov., a thiophene-2-carboxylate-metabolizing bacterium from activated sludge

Arch Microbiol. 1998 Apr;169(4):293-302. doi: 10.1007/s002030050575.


A gram-negative bacterium was isolated from activated sewage sludge with thiophene-2-carboxylate as the sole source of carbon and with nitrate as an electron acceptor. The isolate, strain NKK, was a motile, oxidase- and catalase-positive, rod-like bacterium with a G+C content of 61.7 mol%. Besides nitrate, oxygen could serve as a terminal electron acceptor. Among many carbon sources tested, only a few sugars, fatty acids, and thiophene-2-carboxylate supported growth. Other heterocyclic compounds were not used. The sulfur atom of thiophene-2-carboxylate was oxidized to thiosulfate when cells were grown aerobically, or to elemental sulfur when cells were grown anaerobically with nitrate. Nitrate was reduced to nitrite. Growth on thiophene-2-carboxylate was dependent on the addition of molybdate to the medium. Tungstate, a specific antagonist of molybdate, inhibited growth on thiophene-2-carboxylate at concentrations > 10(-7) M. Three inducible enzymes involved in the metabolism of thiophene-2-carboxylate were detected: an ATP-, CoA-, thiophene-2-carboxylate- and Mg2+-dependent thiophene-2-carboxyl-CoA ligase (AMP-forming), a molybdenum-containing thiophene-2-carboxyl-CoA dehydrogenase, and a thiophene-2-carboxyl-CoA thioesterase. The sequence of the 16S rRNA gene suggested a classification of strain NKK within the alpha-subgroup of the Proteobacteria as a new genus and species, Aquamicrobium defluvii gen. nov. sp. nov. (DSM 11603), closely related to Mesorhizobium sp. and Phyllobacterium sp., but representing a distinct lineage equal in depth to those of the two mentioned genera. Aquamicrobium defluvii can be distinguished from both genera by a distinct spectrum of substrates, the maximal growth temperature, and a different salt tolerance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carboxylic Acids
  • Cell Division / drug effects
  • Coenzyme A Ligases / drug effects
  • Coenzyme A Ligases / metabolism
  • DNA, Ribosomal / analysis
  • DNA, Ribosomal / genetics
  • Gram-Negative Bacteria / genetics
  • Gram-Negative Bacteria / isolation & purification*
  • Gram-Negative Bacteria / metabolism
  • Microbiological Techniques
  • Molybdenum / pharmacology
  • Palmitoyl-CoA Hydrolase / drug effects
  • Palmitoyl-CoA Hydrolase / metabolism
  • Phylogeny
  • RNA, Ribosomal, 16S / genetics
  • Sewage / microbiology*
  • Soil Microbiology*
  • Thiophenes / metabolism*
  • Thiophenes / pharmacology
  • Tungsten Compounds / pharmacology


  • Carboxylic Acids
  • DNA, Ribosomal
  • RNA, Ribosomal, 16S
  • Sewage
  • Thiophenes
  • Tungsten Compounds
  • molybdate
  • 2-thiophene carboxylic acid
  • Molybdenum
  • Palmitoyl-CoA Hydrolase
  • Coenzyme A Ligases
  • tungstate

Associated data

  • GENBANK/Y15403