COMETABOLISM OF 1,1-DICHLORO-2,2-BIS(4-CHLOROPHENYL)ETHYLENE BY PSEUDOMONAS ACIDOVORANS M3GY GROWN ON BIPHENYL

1,1-Dichloro-2,2-bis(4-chlorophenyl)ethylene (DDE), a toxic breakdown product of 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT), has tr aditionally been viewed as a dead-end metabolite: there are no publish ed reports detailing enzymatic ring fission of DDE by bacteria in eith er soil or pure culture. In this study, we investigated the ability of Pseudomonas acidovorans M3GY to transform DDE and its unchlorinated a nalog, 1,1-diphenylethylene (DPE). While strain M3GY could grow on DPE , cells grown on DPE as a sole carbon source could not degrade DDE. Ce lls grown on biphenyl, however, did degrade DDE. Mass balance analysis of [C-14]DDE showed transformation of more than 40% of the recoverabl e radioactivity. Nine chlorinated metabolites produced from DDE were i dentified by gas chromatography-mass spectrometry-Fourier-transform in frared spectrometry (GC-MS-FTIR) from cultures grown on biphenyl. Reco very of these metabolites demonstrates that biphenyl-grown cells degra de DDE through a meta-fission pathway. This study provides a possible model for biodegradation of DDE in soil by biphenyl-utilizing bacteria .