Microbial reduction of crystalline iron(III) oxides: Influence of oxide surface area and potential for cell growth
- Univ. of Alabama, Tuscaloosa, AL (United States)
- Battelle Pacific National Lab., Richland, WA (United States)
Quantitative aspects of microbial crystalline iron(III) oxide reduction were examined using a dissimilatory iron(III) oxide-reducing bacterium (Shewanella alga strain BrY). The initial rate and long-term extent of reduction of a range of synthetic iron(III) oxides were linearly correlated with oxide surface area. Oxide reduction rates reached an asymptote at cell concentrations in excess of =1 x 10{sup 9}/m{sup 2} of oxide surface. Experiments with microbially reduced goethite that had been washed with pH 5 sodium acetate to remove adsorbed Fe(II) suggested that formation of a Fe(II) surface phase (adsorbed or precipitated) limited the extent of iron(III) oxide reduction. These results demonstrated explicitly that the rate and extent of microbial iron (III) oxide reduction is controlled by the surface area and site concentration of the solid phase. Strain BrY grew in media with synthetic goethite as the sole electron acceptor. The quantity of cells produced per micromole of goethite reduced (2.5 x 10{sup 6})was comparable to that determined previously for growth of BrY and other dissimilatory Fe(III)-reducing bacteria coupled to amorphous iron(III) oxide reduction. BrY reduced a substantial fraction (8-18%) of the crystalline iron(III) oxide content of a variety of soil and subsurface materials, and several cultures containing these materials were transferred repeatedly with continued active Fe(III) reduction. 77 refs., 9 figs., 2 tabs.
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 249728
- Journal Information:
- Environmental Science and Technology, Vol. 30, Issue 5; Other Information: PBD: May 1996
- Country of Publication:
- United States
- Language:
- English
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