Speaker : Clive Butler, School of Biological Sciences, University of Exeter
Location: Ridley building 1.63
Time/Date: 3rd March 2010, 16:00
Respiratory flexibility permits microbes to populate a diverse range of habitats and facilitates their use in many bioremediation applications. It is the potential to use a number of different terminal electron acceptors that gives them the selective advantage to survive and colonize many of the most extreme and hostile anoxic environments. One such adaptation is the ability of some bacteria to utilise toxic metalloid oxyanions such as selenate and selenite as respiratory substrates. Selenate is the most oxidised form of selenium (Se); it is highly soluble and can present a significant hazard to health and the environment. Naturally high levels of selenate are found in America and Canada, where for example, selenate contaminated drainage water from the seleniferous rich soils has been a major cause of death and deformities in the inhabiting wildlife. However, it is more commonly human activities such as petroleum refining, mining and fossil fuel combustion that result in generating selenate contamination. These soluble oxyanions (selenate and selenite) are the primary forms of selenium in aerated environments and their transformation to elemental selenium and selenide containing compounds occurs primarily by microbial processes. Consequently, microbes capable of the precipitation of non-toxic elemental selenium are of considerable interest to those developing environmental cleansing and remediation strategies. We have undertaken a detailed biochemical analysis of the pathways for selenate and selenite reduction by the bacterium Thauera selenatis and have revealed some novel and interesting mechanisms for selenate respiration and selenium precipitation.
Host: Ian Singleton
Published: 25th January 2010