Reduction of Cr(VI) by Palladized -: Biomass of Desulfovibrio desulfuricans ATCC 29577

A novel catalytic activity of palladium [Pd(O)]-coated cells of Desulfovibrio desulfuricans ATCC 29577 [bio-Pd(O)] is demonstrated. Reduction of 700 muM Cr(VI) occurred within 24 h using formate (25 mM) or hydrogen (1 atm) as the electron donor, under conditions whereby cells lacking bound Pd(O), or palladium metal manufactured via chemical reduction of soluble Pd(II), did not reduce Cr(VI). The biomass-bound Pd(O) also functioned in the continuous removal of 400 muM Cr(VI) from a 1 mM solution under H-2 (flow residence time approximately 5 h), where chemically prepared Pd(O) was ineffective. This demonstrates a new type of active bioinorganic catalysis, whereby the presence of biomass bound to Pd(O) confers a novel catalytic capability not seen with Pd base metal or biomass alone. (C) 2004 Wiley Periodicals, Inc.