Prof. Dr. Thorsten Stumpf

Director Institute of Resource Ecology
Phone: +49 351 260 3210

PhD Thesis

Interaction and Speciation of Selected Actinides (U, Cm) with Microorganisms Relevant to Nuclear Waste Disposal

Pic Lütke

PhD student:
Laura Frost
Prof. Dr. G. Bernhard, Dr. H. Moll (HZDR)

Motivation & Aims

Bacteria belong to the most widely spread organisms in nature. Besides archaea, these organisms represent the only form of life which can inhabit hostile environments of e.g. high salinity, temperature and radiation, like designated nuclear waste disposal sites. Microorganisms present in groundwater and subterranean soil environments can interact with actinyl ions through multiple pathways, affecting their speciation and eventually their distribution in the environment. Hence it is necessary to elucidate the interaction mechanisms with microbes isolated from designated nuclear waste disposal sites.

As part of the BMWi-funded project "Microbial Diversity in Clay Stone (Opalinus Clay) and Interaction of Dominant Microorganisms with Actinides" (project coordination: Dr. H. Moll), the aim of this study is to investigate the interaction of the clay isolate Paenibacillus sp. nov. with U(VI) and Cm(III). Furthermore the interaction of U(VI) with Pseudomonas fluorescens, a strain isolated from the granitic aquifers at Äspö, Sweden, is studied. Specific emphasis is placed on the characterization of the actinide coordination at the cell surface on a molecular level. This is especially done using potentiometric titration as well as direct speciation techniques (time-resolved laser-induced fluorescence spectroscopy, TRLFS) and structural analyses (XAS).


  • Frost, L., Osman, A. A., Geipel, G., Viehweger, K., Moll, H., Bernhard, G. (2011) The interaction of U(VI) with some bioligands or the influence of different functional groups on complex formation. The New Uranium Mining Boom, 595-606, Springer, Berlin.
  • Frost, L., Geipel. G., Viehweger, K., Bernhard, G. (2011) Interaction of uranium(VI) towards glutathione – an example to study different functional groups in one molecule. Proc. Radiochim. Acta 1, 357–362.
  • Lütke, L., Moll, H., Bernhard, G. (2012) A new uranyl benzoate species characterized by different spectroscopic techniques. Radiochim. Acta 100, 1–7.
  • Moll, H., Lütke, L., Barkleit, A., Bernhard, G. (2012) Curium(III) speciation studies with cells of a groundwater strain of Pseudomonas fluorescens. Geomicrobiol. J., submitted.
  • Lütke, L., Moll, H., Bernhard, G. (2012) Insights on the uranium(VI) speciation with Pseudomonas fluorescens on a molecular level. In preparation.