Cr(III) is indirectly oxidized by the Mn(II)-oxidizing bacterium Bacillus sp. strain SG-1

Karen J. Murray, Bradley Tebo

Research output: Contribution to journalArticle

63 Citations (Scopus)

Abstract

Manganese oxides are the only known oxidants of Cr(III) in the environment, and predictions of the fate of Cr(III) have been based on Cr(III) oxidation rates with well-characterized Mn(III,IV) oxide minerals. Our research, however, indicates that the presence of Mn(II)-oxidizing bacteria may accelerate these rates through the production of very reactive Mn oxides or intermediates formed in the oxidation process. Experiments with the Mn(II)-oxidizing Bacillus sp. strain SG-1 show that this bacterium can accelerate Cr(III) oxidation compared to both abiotic and biologically produced Mn oxides. Initial rates of Cr(III) oxidation by biogenic oxides were approximately 7 times faster than Cr(III) oxidation rates by equivalent amounts of synthetic δ-MnO2 and 25 times faster by SG-1 spores with Mn(II). Cr(III) oxidation by SG-1 is not direct; Mn is required, but only in small amounts, indicating that it is recycled. Cr(III) oxidation is inhibited above 5 μM dissolved Mn(II), while Mn(II) oxidation is not, suggesting that the processes are controlled by different mechanisms. These results illustrate the need to consider bacterial activity and the concentration of Mn when predicting the potential for Cr(III) oxidation.

Original languageEnglish (US)
Pages (from-to)528-533
Number of pages6
JournalEnvironmental Science and Technology
Volume41
Issue number2
DOIs
StatePublished - Jan 15 2007

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Bacilli
Bacteria
oxidation
Oxidation
bacterium
oxide
Oxides
Oxide minerals
Manganese oxide
manganese oxide
Oxidants
oxidant
microbial activity
spore
rate
mineral
prediction

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Science(all)
  • Environmental Chemistry

Cite this

Cr(III) is indirectly oxidized by the Mn(II)-oxidizing bacterium Bacillus sp. strain SG-1. / Murray, Karen J.; Tebo, Bradley.

In: Environmental Science and Technology, Vol. 41, No. 2, 15.01.2007, p. 528-533.

Research output: Contribution to journalArticle

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