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1,1-Dichloro-2,2-bis( p-chlorophenyl)ethylene (DDE) is the peri-chlorinated derivative of 1,1-diphenylethylene (DPE). Biodegradation of DDE and DPE by bacteria has so far not been shown. Pure cultures of aerobic bacteria involved in biodegradation of styrene and polychlorinated biphenyls (PCB) were therefore screened for their ability to degrade or cometabolize DPE and DDE. Styrene-metabolizing bacteria ( Rhodococcus strains S5 and VLB150) grew with DPE as their sole source of carbon and energy. Polychlorinated-biphenyl-degrading bacteria ( Pseudomonas fluorescens and Rhodococcus globerulus) were unable to degrade DPE even in the presence of an easily utilizable cosubstrate, biphenyl. This is the first report of the utilization of DPE as sole carbon and energy source by bacteria. All the tested bacteria failed to degrade DDE when it was provided as the sole carbon source or in the presence of the respective degradable cosubstrates. DPE transformation could also be detected in cell-free extracts of Rhodococcus S5 and VLB150, but DDE was not transformed, indicating that cell wall and membrane diffusion barriers were not limiting biodegradation. The results of the present study show that, at least for some bacteria, the chlorination of DDE is the main reason for its resistance to biodegradation by styrene and DPE-degrading bacteria. [ABSTRACT FROM AUTHOR]

2,4-Dimethylphenoxyacetic acid and 2,4-dimethylphenol are not growth substrates for Alcaligenes eutrophus JMP 134 although being cooxidized by 2,4-dichlorophenoxyacetate grown cells. None of the relevant catabolic pathways were induced by the dimethylphenoxyacetate. 3,5-Dimethylcatechol is not subject to metacleavage. The alternative ortho-eleavage is also unproductive and gives rise to (+)-4-carboxymethyl-2,4-dimethylbut-2-en-4-olide as a dead-end metabolite. High yields of this metabolite were obtained with the mutant Alcaligenes eutrophys JMP 134-1 which constitutively expresses the genes of 2,4-dichlorophenoxyacetic acid metabolism. [ABSTRACT FROM AUTHOR]