Effect of complexing agents on reduction of Cr(VI) by Desulfovibrio vulgaris ATCC 29579

Abstract

The reduction of Cr(VI) at the expense of molecular hydrogen was studied using resting cells of Desulfovibrio vulgaris ATCC 29579 in anaerobic resting cell suspensions in MOPS buffer. Bioreduction occurred only in the presence of ligands or chelating agents (CO32-, citrate, NTA, EDTA, DTPA). The stimulatory effect of these ligands on the rate of Cr(VI) reduction was correlated (r = 0.988) with the strength of the ligand/chelate complex of Cr(III). The data are examined with respect to likely solution and redox equilibria in the ionic matrix of the carrier solution, and with respect to the potential for bioremediation of Cr(VI).

Involvement of hydrogenases in the formation of highly catalytic Pd(0) nanoparticles by bioreduction of Pd(II) using Escherichia coli mutant strains

“…The reaction was initiated by the addition of sodium formate (1 ml, 25 mM final concentration) and a sample was withdrawn immediately for estimation of the initial Cr(VI) concentration. Timed samples were successively withdrawn, centrifuged (12 000 g, 4 min; IEC Centra M bench centrifuge) and supernatants were assayed by the diphenyl carbazide method (Mabbett et al, 2002) to estimate the residual Cr(VI) concentration. Removal of Cr(VI) was expressed as the percentage of Cr(VI) removed from the solution as compared to the initial concentration.…”

Enzymatic Chromium (VI) Reduction by Cytoplasmic and Cell Membrane Fractions of Chromate-Reducing Bacterium Isolated From Sewage Treatment Plant

“…Glucose, by active uptake, enhances the biosynthesis of chromate reductase as mentioned in Figure 7. Studies by Mabbett et al (2002) show the presence of low molecular organic molecules such as citrate protected the chromate reductase enzymes from inactivation by removing toxic products of microbial reduction and a close connection between the amount of Cr (VI) reduced and equilibrium constants of Cr-ligand complexes with more Cr (VI) being reduced with much stronger complexes. Succinate, on the other hand, did not show any (Bae et al, 2005).…”

Reduction of Cr(VI) by “palladized” biomass of Desulfovibrio desulfuricans ATCC 29577

“…Previous studies have demonstrated that resting cells of D. vulgaris ATCC 29579 (Lovley and Phillips, 1994;Mabbett et al, 2002) and a new Desulfovibrio sp. (Oz7) isolated from a metal-contaminated site were able reduce Cr(VI) at concentrations of V500 AM, but only in the presence of a ligand species able to complex the Cr(III) product (Mabbett et al, 2002).…”

“…(Oz7) isolated from a metal-contaminated site were able reduce Cr(VI) at concentrations of V500 AM, but only in the presence of a ligand species able to complex the Cr(III) product (Mabbett et al, 2002). The addition of complexing agents may be impractical or uneconomical industrially.…”

“…Cr(VI) was assayed using Cr(VI)-specific diphenylcarbazide (DPC) (Mabbett et al, 2002). The total soluble chromium was measured in filtrates (0.2 Am filter) using ICP-AES (inductively coupled plasma atomic emission spectroscopy) with a Philips ICP-AES device (Model PU7450).…”