Involvement of iron oxidation enzyme system in sulfur oxidation of Acidithiobacillus ferrooxidans ATCC 23270

Taher M. Taha, Tadayoshi Kanao, Fumiaki Takeuchi, Tsuyoshi Sugio

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

4 Citations (Scopus)


Growth of A. ferrooxidans ATCC 23270 cells in sulfur medium with 0.005% ferric sulfate for 3, 4, 5, 6, 7 and 10 days gave the maximum growth yield of 45, 58, 76, 86, 90 and 95 mg protein per liter medium, respectively. Iron oxidase activities of 1-, 2- and 3- day-cultured cells on sulfur with 0.005% ferric sulfate (3.4, 3.5 and 0.8 μmol Fe2+ oxidized/mg protein/min) were approximately 68, 70 and 16% of iron-grown ATCC 23270 cells (5.0 μmol/mg protein/min). In contrast iron oxidase activities of 1-, 2- and 3-day cultured cells on sulfur without iron (4.9, 3.8 and 2.7 umol Fe 2+ oxidized/mg protein/min) were approximately 98, 76 and 54% of the iron oxidase activity observed in iron-grown ATCC 23270 cell. SFORase activities of 3 day-cultured cell on sulfur with and without ferric sulfate (0.62 and 0.31 umol Fe2+ produced/mg protein/min) were approximately 20 and 10 fold higher than that of iron-grown cell (0.03 μmol Fe2+ produced/mg protein/min). Both iron oxidase and SFORase activities increased at early-log phase and decreased at late-lag phase during growth of the strain on sulfur with or without Fe3+. The plasma membranes which had iron oxidase activity were prepared not only from iron-grown cells but also sulfur-grown cells. Iron oxidase activities of the plasma membranes prepared from sulfur- and iron-grown cells were 3.6 and 4.5 nmol Fe2+ oxidized per mg protein per min. These results suggest that iron oxidation enzyme system has a role in part in the energy generation of this bacterium from sulfur.

Original languageEnglish
Title of host publicationBiohydrometallurgy
Subtitle of host publicationFrom the Single Cell to the Environment
PublisherTrans Tech Publications
Number of pages4
ISBN (Print)0878494529, 9780878494521
Publication statusPublished - Jan 1 2007
Event17th International Biohydrometallurgy Symposium, IBS 2007 - Frankfurt am Main, Germany
Duration: Sept 2 2007Sept 5 2007

Publication series

NameAdvanced Materials Research
ISSN (Print)1022-6680


Other17th International Biohydrometallurgy Symposium, IBS 2007
CityFrankfurt am Main


  • Acidithiobacillus ferrooxidans
  • Iron oxidase
  • Sulfur oxidation

ASJC Scopus subject areas

  • Engineering(all)


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