RECALCITRANCE OF 1,1-DICHLORO-2,2-BIS(P-CHLOROPHENYL)ETHYLENE (DDE) TO COMETABOLIC DEGRADATION BY PURE CULTURES OF AEROBIC AND ANAEROBIC-BACTERIA

Pure cultures of aerobic and anaerobic bacteria capable of oxidation a nd reductive dehalogenation of chloroethylenes, and aerobic bacteria i nvolved in biodegradation of polychlorinated biphenyls (PCBs) were scr eened for their ability to cometabolize the persistent pollutant 1,1-d ichloro-2,2-bis(p-chlorophenyl)ethylene (DDE). Bacterial cultures expr essing methane monooxygenase (Methylosinus trichosporium), propane mon ooxygenase (Mycobacterium vaccae) and biphenyl 2,3-dioxygenase enzymes (Pseudomonas fluorescens and Rhodococcus globerulus), as well as bact eria reductively dechlorinating chloroethylenes (Acetobacterium woodii and Clostridium butyricum) could not degrade DDE. Cell-free extracts of M. trichosporium, M. vaccae, P. fluorescens and R. globerulus were also unable to transform DDE, indicating that cell wall and membrane d iffusion barriers were not biodegradation limiting. These studies sugg est that these bacteria can not degrade DDE, even when provided with c osubstrates that induce chlorophenyl-and dichloroethylene-group transf orming enzymes.