Existence of ferrous iron-dependent mercury reducing enzyme system in sulfur-grown A. ferrooxidans MON-1 cells

Tsuyoshi Sugio, Taher M. Taha, Atsunori Negishi, Fumiaki Takeuchi

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

Iron-grown Acidithiobacillus ferrooxidans MON-1 cells are highly resistant to organomercurial compounds as well as mercuric chloride (HgCl2). Existence of a novel Hg2+-reducing enzyme system, in which mercury resistant aa3-type cytochrome c oxidase catalyzes the reduction of Hg2+ with reduced mammalian cytochrome c or Fe2+ as an electron donor to give Hg0, has been shown in iron-grown MON-1 cells. There has been no reports on the mechanism of Hg2+ reduction by sulfur-grown A. ferrooxidans cells. The level of mercury resistance in sulfur-grown A. ferrooxidans MON-1 cells was compared with that of iron-grown MON-1 cells. Strain MON-1 was able to grow in 1% elemental sulfur medium (pH 2.5) containing 10 μM of Hg2+ or 0.2 μM phenylmercury acetate (PMA), suggesting that the levels of mercury resistance to inorganic and organic mercurial compounds are nearly the same in iron- and sulfur-grown MON-1 cells. Activity levels of Hg0 volatilization from HgCl2, PMA, and methylmercury chloride (MMC) were also nearly the same in iron- and sulfur-grown cells and these activities were markedly activated by 100 mM of Fe2+, but strongly inhibited by 1 mM of sodium cyanide, indicating that sulfur-grown MON-1 cells has the activity of ferrous iron-dependent mercury reducing enzyme system containing aa3-type cytochrome oxidase. aa3-type cytochrome c oxidase purified partially from sulfur-grown MON-1 cells showed both the iron oxidase and mercury reductase activities in the presence, but not in the absence, of rusticyanin and c-type cytochromes (Cyc1 and Cyc2) partially purified from iron-grown MON-1 cells.

Original languageEnglish
Title of host publicationBiohydrometallurgy 2009
Subtitle of host publicationA Meeting Point between Microbial Ecology, Metal Recovery Processes and Environmental Remediation - Selected, peer rev. papers 18th Int. Biohydrometallurgy Symp., IBS 2009
Pages745-748
Number of pages4
DOIs
Publication statusPublished - Dec 28 2009
Event18th International Biohydrometallurgy Symposium, IBS 2009 - Bariloche, Argentina
Duration: Sep 13 2009Sep 17 2009

Publication series

NameAdvanced Materials Research
Volume71-73
ISSN (Print)1022-6680

Other

Other18th International Biohydrometallurgy Symposium, IBS 2009
CountryArgentina
CityBariloche
Period9/13/099/17/09

Keywords

  • Acidithiobacillus ferrooxidans
  • Cytochrome c oxidase
  • Mercury reduction
  • Organomercurial compound
  • Sulfur

ASJC Scopus subject areas

  • Engineering(all)

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    Sugio, T., Taha, T. M., Negishi, A., & Takeuchi, F. (2009). Existence of ferrous iron-dependent mercury reducing enzyme system in sulfur-grown A. ferrooxidans MON-1 cells. In Biohydrometallurgy 2009: A Meeting Point between Microbial Ecology, Metal Recovery Processes and Environmental Remediation - Selected, peer rev. papers 18th Int. Biohydrometallurgy Symp., IBS 2009 (pp. 745-748). (Advanced Materials Research; Vol. 71-73). https://doi.org/10.4028/www.scientific.net/AMR.71-73.745