Sulphate-reducing bacteria, palladium and the reductive dehalogenation of chlorinated aromatic compounds

The surfaces of cells of Desulfovibrio desulfuricans,Desulfovibrio vulgaris and a new strain, Desulfovibrio sp. `Oz-7' were used to manufacturea novel bioinorganic catalyst via the reduction of Pd(II) to Pd(0) at the cell surface usinghydrogen as the electron donor. The ability of the palladium coated (palladised) cells to reductivelydehalogenate chlorophenol and polychlorinated biphenyl species was demonstrated. Dried, palladisedcells of D. desulfuricans, D. vulgaris and Desulfovibrio sp. `Oz-7'were more effective bioinorganic catalysts than Pd(II) reduced chemically under H2 orcommercially available finely divided Pd(0). Differences were observed in the catalyticactivity of the preparations when compared with each other. Negligible chloride release occurredfrom chlorophenol and polychlorinated biphenyls using biomass alone.