| Abstract
| - Toxaphene is a complex organochlorine pesticide mixture,residues of which are widespread in the environment.Previous studies with the isolated bacterium Sulfurospirillum(formerly Dehalospirillum) multivorans resulted in aneffective anaerobic biotransformation of toxaphene. Sincethe bacterium contains a corrinoid derivative in theactive center of the tetrachloroethene dehalogenase, weattempted to use superreduced corrinoids for abiotictransformation of toxaphene. The two corrinoids studiedwere dicyanocobinamide and cyanocobalamin (vitamin B12).Superreduced dicyanocobinamide mediated a rapidtransformation of toxaphene. More than 90% of the initialpool was transformed within 6 h. The transformationwas nonselective, and even the most persistent metabolitein environmental samples, the so-called dead-end metab-olite 2-exo,3-endo,6-exo,8,9,10-hexachlorobornane (B6-923or Hx-Sed) was transformed within hours. Superreducedcyanocobalamin was also able to transform toxaphene albeitat significantly lower velocity. The lack of transformationproducts detectable in gas chromatograms of hexanes-extracted fractions of the assays suggests rapid, sequentialdehalogenation and/or destruction of the C10-hydrocarbonbackbone of the compounds of technical toxaphene.
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