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Archives of Microbiology

, Volume 169, Issue 4, pp 293–302 | Cite as

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

  • Andreas Bambauer
  • Fred A. Rainey
  • Erko Stackebrandt
  • J. Winter
Original paper

Abstract

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 α-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.

Key wordsAquamicrobium defluvii Thiophene-2-carboxylic acid Thiophene-2-carboxy-CoA ligase Thiophene-2-carboxyl-CoA thioesterase Thiophene-2-carboxyl-CoA dehydrogenase Thiosulfate Sulfur Molybdenum Nitrate Nitrite 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1998

Authors and Affiliations

  • Andreas Bambauer
    • 1
  • Fred A. Rainey
    • 2
  • Erko Stackebrandt
    • 3
  • J. Winter
    • 1
  1. 1.Institut für Ingenieurbiologie und Biotechnologie des Abwassers, Universität Karlsruhe, Am Fasanengarten, D-76128 Karlsruhe, Germany Tel. +49-721-608-2297; Fax +49-721-694826 e-mail: josef.winter@bau-verm.uni-karlsruhe.deDE
  2. 2.Department of Microbiology, Life Science Building, Louisiana State University, Baton Rouge, 70803, Louisiana, USAUS
  3. 3.Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Mascheroder Weg 1 b, D-38124 Braunschweig, GermanyDE

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