Control of nanoparticle size, reactivity and magnetic properties during the bioproduction of magnetite by Geobacter sulfurreducens

J. M. Byrne, N. D. Telling, V. S. Coker, R. A D Pattrick, G. Van Der Laan, E. Arenholz, F. Tuna, J. R. Lloyd

    Research output: Contribution to journalArticlepeer-review


    The bioproduction of nanoscale magnetite by Fe(III)-reducing bacteria offers a potentially tunable, environmentally benign route to magnetic nanoparticle synthesis. Here, we demonstrate that it is possible to control the size of magnetite nanoparticles produced by Geobacter sulfurreducens by adjusting the total biomass introduced at the start of the process. The particles have a narrow size distribution and can be controlled within the range of 10-50nm. X-ray diffraction analysis indicates that controlled production of a number of different biominerals is possible via this method including goethite, magnetite and siderite, but their formation is strongly dependent upon the rate of Fe(III) reduction and total concentration and rate of Fe(II) produced by the bacteria during the reduction process. Relative cation distributions within the structure of the nanoparticles have been investigated by x-ray magnetic circular dichroism and indicate the presence of a highly reduced surface layer which is not observed when magnetite is produced through abiotic methods. The enhanced Fe(II)-rich surface, combined with small particle size, has important environmental applications such as in the reductive bioremediation of organics, radionuclides and metals. In the case of Cr(VI), as a model high-valence toxic metal, optimized biogenic magnetite is able to reduce and sequester the toxic hexavalent chromium very efficiently to the less harmful trivalent form. © 2011 IOP Publishing Ltd.
    Original languageEnglish
    Article number455709
    Issue number45
    Publication statusPublished - 11 Nov 2011


    • 2p absorption-spectra
    • x-ray-absorption
    • mineralization pathways
    • fept nanoparticles
    • circular-dichroism
    • aqueous cr(vi)
    • reduction
    • iron
    • ferrihydrite
    • spectroscopy


    Dive into the research topics of 'Control of nanoparticle size, reactivity and magnetic properties during the bioproduction of magnetite by Geobacter sulfurreducens'. Together they form a unique fingerprint.

    Cite this