Poster: Phytoremediation

Abs # 976: Metabolism of Halogenated Hydrocarbons by Plant Cells

Presenter:	Doty, Sharon L, sldoty@u.washington.edu
Authors	Doty, Sharon L (A)   Gordon, Milton P (A)   Strand, Stuart E (B)
Affiliations:	(A): University of Washington, Dept. of Biochemistry (B): University of Washington, College of Forest Resources

Trichloroethylene (TCE) is a wide-spread groundwater and soil pollutant. A variety of plants, including poplar, tobacco, and L. leucocephala are capable of metabolizing TCE to some degree. A common intermediate metabolite of TCE is trichloroethanol. In transgenic plants expressing mammalian cytochrome P450 2E1, the levels of this intermediate were high compared to in non-transgenic plants. For phytoremediation of TCE to be successful, dechlorination of TCE must also be achieved in order to decrease the toxicity of the pollutant and its metabolites. We have developed a simple assay for determining the ability of plant cells to dehalogenate the pollutant using tribromoethanol as a surrogate for trichloroethanol. Debromination of tribromoethanol is more easily detected than dechlorination of trichloroethanol since chloride ion is ubiquitous and at relatively high background levels in plants compared with bromide ion. We have demonstrated that poplar cells can dehalogenate tribromoethanol, leading to the release of harmless bromide ion. Cloning of the dehalogenase from poplar is underway.