DEFLUORINATION OF ORGANOFLUORINE SULFUR-COMPOUNDS BY PSEUDOMONAS SP. STRAIN D2

Little is known of the potential for biodegradation of fluorinated sul fonates. To evaluate this potential, the following model compounds wer e selected: difluoromethane sulfonate (DFMS), trifluoromethane sulfona te (TFMS), 2,2,2-trifluoroethane sulfonate (TES), perfluorooctane sulf onate (PFOS), and 1H,1H,2H,2H-perfluorooctane sulfonate (H-PFOS). A la boratory isolate designated Pseudomonas sp, strain D2 completely deflu orinated DFMS under aerobic, sulfur-limiting conditions in a defined m ineral medium. Strain D2 utilized DFMS as the sole source of sulfur, b ut not as a source of carbon or energy. DFMS utilization was inhibited by other forms of sulfur, and noncompetitive inhibition kinetics were observed, with K-i values of 3-4 mu M for sulfate, sulfite, methane s ulfonate, and cystine. Strain D2 was subsequently used to evaluate deg radation of other fluorinated sulfonates. Growth and defluorination we re only observed for those compounds containing hydrogen (TES and H-PF OS). TFMS and PFOS were not degraded. TES was completely defluorinated , and H-PFOS was partially defluorinated. No volatile transformation p roducts were detected for TES or DFMS, but six volatile products were detected for H-PFOS. All of the volatile products contained oxygen and fluorine, but not sulfur. This is the first report of defluorination of fluorinated sulfonates, a linkage between sulfur assimilation and d efluorination, and generation of volatile fluorinated biotransformatio n products.