Bennett Nwaobi - Research Student

Telephone: 25785
Room: G22 Kroto Research Institute

email : cip04bn@sheffield.ac.uk

Research Group

Research Project

Metal - bacteria interactions at the mineral surface: modelling of the process and mechanistic implications.

The project involves the study of cell-mineral interactions in the presence of uranyl and other oxyanion metalloid species as model systems for the fundamental study cellular interactions with metal species in the aqueous environment. The motivation is that the combination of surface spectroscopic methods with aqueous chemistry have generally not been applied to study living cells. We will focus on the surface coordination environment for U(VI) species in the presence of the Gram-negative bacterium Acidithiobacillus ferrooxidans and will compare with additional metal oxyanions, such as arsenic and chromium species.

Uranium accumulating microorganisms in natural environments have been studied by molecular biology techniques including PCR and ribotyping, identifying three different strains of A. ferrooxidans with different capacities for uranium complexation and accumulation. These strains are generally associated with growth on mineral surfaces. Characterisation of the mineral and cell surface binding sites for metal species will be performed quantitatively by potentiometric surface titration and infrared spectroscopy.

For the coordination chemistry studies of metal binding, x-ray absorption spectroscopy as well as electron microscopy will be used to analyse the local environment of metal species and the surface morphology associated with metal accumulation.

The work will be linked to the expertise on cell-mineral adhesion generated by the EPSRC project, "Nanometre-scale observation of biodegradation in soil and groundwater" lead by Prof. S. A. Banwart and involving colleagues from five departments of the University of Sheffield.