Production of a molybdophore during metal-targeted dissolution of silicates by soil bacteria

Laura J. Liermann, Robin L. Guynn, Ariel Anbar, Susan L. Brantley

Research output: Contribution to journalArticle

55 Scopus citations

Abstract

Although many bioessential metals are scarce in natural water and rock systems, microbial secretion of high-affinity ligands for metal extraction from solid phases has only been documented for Fe. However, we have discovered that Mo is extracted from a silicate by a high-affinity ligand (a possible "molybdophore") secreted by an N2-fixing soil bacterium. The putative molybdophore, aminochelin, is secreted as a siderophore under Fe-depleted conditions, but is also secreted under Fe-sufficient, Mo-depleted conditions. Presumably, molybdophore production facilitates uptake of Mo for use in Mo enzymes. In contrast, an Fe-requiring soil bacterium without a special Mo requirement only enhances the release of Fe from the silicate. Fractionation of Mo stable isotopes during uptake to cells may provide a "fingerprint" for the importance of chelating ligands in such systems. Many such metal-specific ligands secreted by prokaryotes for extraction of bioessential metals, their effects on Earth materials, and their possible utility in the recovery of economic metals remain to be discovered.

Original languageEnglish (US)
Pages (from-to)285-302
Number of pages18
JournalChemical Geology
Volume220
Issue number3-4
DOIs
StatePublished - Aug 5 2005

Keywords

  • Aminochelin
  • Azotobacter vinelandii
  • Azotochelin
  • Molybdenum
  • Nitrogenases
  • Siderophores

ASJC Scopus subject areas

  • Geology
  • Geochemistry and Petrology

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