Cr(III) oxidation and Cr toxicity in cultures of the manganese(II)-oxidizing Pseudomonas putida strain GB-1

Karen J. Murray, Mylene L. Mozafarzadeh, Bradley M. Tebo

Research output: Contribution to journalArticle

38 Scopus citations


Mn oxides have long been considered the primary environmental oxidant of Cr(III), however, since most of the reactive Mn oxides in the environment are believed to be of biological origin, microorganisms may indirectly mediate Cr(III) oxidation and accelerate the rate over that seen in purely abiotic systems. In this study, we examined the ability of the Mn(II)-oxidizing bacterium, Pseudomonas putida strain GB-1, to oxidize Cr(III). Our results show that GB-1 cannot oxidize Cr(III) directly, but that in the presence of Mn(II), Cr(III) can be rapidly and completely oxidized. Growth studies suggest that in growth medium with few organics the resulting Cr(VI) may be less toxic to P. putida GB-1 than Cr(III), which is generally considered less hazardous. In addition, Cr(III) present during the growth of P. putida GB-1 appeared to cause iron stress as determined by the production of the fluorescent siderophore pyoverdine. When stressed by Fe limitation or Cr(III) toxicity, Mn(II) oxidation by GB-1 is inhibited.

Original languageEnglish (US)
Pages (from-to)151-159
Number of pages9
JournalGeomicrobiology Journal
Issue number3-4
StatePublished - Apr 1 2005



  • Bioremediation
  • Chromium oxidation
  • Chromium toxicity
  • Manganese
  • Pseudomonas

ASJC Scopus subject areas

  • Microbiology
  • Environmental Chemistry
  • Environmental Science(all)
  • Earth and Planetary Sciences (miscellaneous)

Cite this