Reduction of technetium by Desulfovibrio desulfuricans: Biocatalyst characterization and use in a flowthrough bioreactor
- Univ. of Birmingham, Edgbaston (United Kingdom). School of Biological Sciences
- Russian Academy of Sciences, Moscow (Russian Federation). Inst. of Microbiology
Resting cells of Desulfovibrio desulfuricans coupled the oxidation of a range of electron donors to Tc(VII) reduction. The reduced technetium was precipitated as an insoluble low-valence oxide. The optimum electron donor for the biotransformation was hydrogen, although rapid rates of reduction were also supported when formate or pyruvate was supplied to the cells. Technetium reduction was less efficient when the growth substrates lactate and ethanol were supplied as electron donors, while glycerol, succinate, acetate, and methanol supported negligible reduction. Enzyme activity was stable for several weeks and was insensitive to oxygen. Transmission electron microscopy showed that the radionuclide was precipitated at the periphery of the cell. Cells poisoned with Cu(II), which is selective for periplasmic but not cytoplasmic hydrogenases, were unable to reduce Tc(VII), a result consistent with the involvement of a periplasmic hydrogenase in Tc(VII) reduction. Resting cells, immobilized in a flowthrough membrane bioreactor and supplied with Tc(VII)-supplemented solution, accumulated substantial quantities of the radionuclide when formate was supplied as the electron donor, indicating the potential of this organism as a biocatalyst to treat Tc-contaminated wastewaters.
- OSTI ID:
- 354331
- Journal Information:
- Applied and Environmental Microbiology, Vol. 65, Issue 6; Other Information: PBD: Jun 1999
- Country of Publication:
- United States
- Language:
- English
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