U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings
of the Technical Meeting, Colorado Springs, Colorado, September 20-24, 1993,
Water-Resources Investigations Report 94-4015
Bioremediation of Petroleum and Metal Contamination with Dissimilatory
Derek R. Lovley (U.S. Geological Survey, Reston, Va.)
The possibility that themetabolism of dissimilatory metal-reducingmicroorganisms might be used for removing organiccontaminants
and metals from contaminated environmentswas investigated. The
Fe(III) chelator, nitrilotriaceticacid (NTA) enhanced the degradation
oftoluene in petroleum-contaminated aquifer materialin
which Fe(III) reduction was the terminalelectron-accepting process.
Addition ofFe(III) oxide containing sediments stimulatedtoluene degradation in sediments thatwere originally methanogenic.
These results suggestthat increasing the availability of Fe(III)
maybe a useful bioremediation strategyin aquifers
that are heavily contaminated with aromaticcompounds. Studies
on the mechanism forU(VI) reduction by Desulfovibriovulgaris indicated that cytochrome c3 is the U(VI)
and Cr(VI)reductase. Cytochrome c3 reduced U(VI)
in uranium-contaminatedmine drainage and ground water. This
findingindicates that it may be possible to geneticallyengineer microorganisms with enhanced metal-reducingcapacity.
These studies demonstrate thatdissimilatory metal reduction
may be auseful mechanism for bioremediatingorganic
and (or) metal contamination in someenvironments.