Discovery - University of Dundee - Online Publications

Library & Learning Centre

Removal of selenate from sulfate-containing media by sulfate-reducing bacterial biofilms

Removal of selenate from sulfate-containing media by sulfate-reducing bacterial biofilms

Research output: Contribution to journalArticle

View graph of relations


  • Simon Hockin
  • Geoffrey M. Gadd

Research units


Original languageEnglish
Pages (from-to)816-826
Number of pages11
JournalEnvironmental Microbiology
Issue number5
StatePublished - May 2006


A biofilm-selected strain of a Desulfomicrobium sp. removed selenate from solution to sub-micromolar concentrations during growth on lactate (or hydrogen) and sulfate. Under sulfate-limited growth conditions, selenium was enzymatically reduced to selenide. Under excess sulfate conditions, selenate removal was primarily by enzymatic reduction to elemental selenium. Sequestration by biofilms was greater under the latter condition. Experiments with washed cell suspensions showed that high sulfate concentrations inhibited cell-specific selenate reduction, but when growing cells were exposed to selenate, the biomass increase achieved during incubations with abundant sulfate resulted in more rapid selenate removal. The addition of small amounts of sulfite, or thiosulfate, ameliorated this inhibition. Nitrate also inhibited selenate reduction in washed cell suspensions, apparently due to a general oxidizing effect. These results suggest that where biofilm-based sulfate-reducing bacteria (SRB) bioreactors are considered for the treatment of mixed metalliferous wastes that contain selenium oxyanions, adequate selenate removal should be achievable under a range of environmental conditions. The form and fate of the precipitated product will, however, be influenced by the dominant reduction pathway, which is controlled by environmental variables.



Library & Learning Centre

Contact | Accessibility | Policy