Background and rationale
Fungi and bacteria are the major geoactive agents in terrestrial habitats and can transform Se and Te oxyanions by reduction, which reduces mobility and toxicity (1,2). Se/Te reduction appears to be a widely found property, and has the potential to immobilize these metalloids as elemental Se or Te (3) which can be deposited intracellularly or extracellularly as amorphous, nanoparticulate, -crystalline and -rod morphologies (4-7). Surprisingly little information is available for Se or Te reduction in aerobic organisms although the capability seems ubiquitous (3). Further, almost nothing is known about geochemical influences and limitations on metalloid reduction in aerobic habitats.
The aim of this project is to examine geochemical influence on Se/Te reduction by aerobic microbes, using model systems of simple to intermediate complexity, to identify what limitations there are to the process, and their importance. The influence of other metal and mineral components, organic components and nutrients on metalloid reductive capabilities of geoactive bacterial and fungal strains will be characterised, together with the abilities of strains to effect other metal-mineral transformations. The project will therefore produce fundamental scientific information regarding aerobic Se/Te reduction, and therefore add to our current understanding of Se/Te biogeochemistry. This project is interdisciplinary and the student will receive training in geomicrobiology and environmental mineralogy with associated analytical and preparative techniques, including growth and manipulation of experimental organisms, and techniques including atomic absorption spectrophotometry (AAS), X-ray powder diffraction (XRPD), and advanced light and electron microscopy, X-ray element analysis and mapping. The student will directly interact with other groups in a large NERC-funded research consortium, will receive cross-disciplinary training in geomicrobiology and geomycology, environmental geochemistry and mineralogy, and will interact with other ongoing research projects and training networks, e.g. UK Geomicrobiology Network, that are concerned with metal mobility in the environment. Applicants should ideally have a first-class or upper second class degree in microbiology, geomicrobiology, environmental mineralogy or a related discipline, experience of microbial growth and culture, and a good knowledge of organic and inorganic chemistry. Applications are invited now for a potential start date in September/October 2016.
Applications are invited now for a potential start date in September/October 2016 and are funded for a period of 3.5 years. The deadline for applications is set as the 31st July 2016.
Applications are invited from UK/EU residents who fulfil NERC eligibility criteria. Applications from non-UK/EU nationals for these project areas can only be considered if applicants have their own funding.
(1) Gadd, G.M. Metals, minerals and microbes: geomicrobiology and bioremediation. Microbiology 156, 609 – 643 (2010).
(2) Glasauer, S.M., Beveridge, T.J., Burford, E.P., Harper, F.A., Gadd, G.M. Metals and metalloids, transformation by microorganisms. In: Elsevier Reference Module: Earth Systems and Environmental Sciences, pp. 1-11 (2013).
(3) Gharieb, M.M., Wilkinson, S.C., Gadd, G.M. Reduction of selenium oxyanions by unicellular, polymorphic and filamentous fungi: cellular location of reduced selenium and implications for tolerance. Journal of Industrial Microbiology 14, 300-311(1995).
(4) Hockin, S., Gadd, G.M. Removal of selenate from sulphate-containing media by sulphate-reducing bacterial biofilms. Environmental Microbiology 8, 816-826 (2006).
(5) Hockin, S., Gadd, G.M. Linked redox-precipitation of sulfur and selenium under anaerobic conditions by sulfate-reducing bacterial biofilms. Applied and Environmental Microbiology 69, 7063-7072 (2003).
(6) Oremland, R. S. et al. Structural and spectral features of selenium nanospheres formed by Se-respiring bacteria. Applied and Environmental Microbiology 70, 52-60 (2004).
(7) Baesman, S.M. et al. Formation of tellurium nanocrystals during anaerobic growth of bacteria that use Te oxyanions as respiratory electron acceptors. Applied and Environmental Microbiology 73, 2135-2143 (2007).