Recruitment of co-metabolic enzymes for environmental detoxification of organohalides

Polyhalogenated compounds are often environmentally persistent and toxic to mammals. Microorganisms that metabolize these compounds can detoxify contaminated environments. Different biochemical mechanisms are used to metabolize polyhalogenated compounds, but few naturally occurring bacteria have this capability. A recombinant bacterium was constructed to metabolize polyhalogenated compounds to non-halogenated end products. Seven genes were expressed in Pseudomonas putida G786 to biosynthesize cytochrome P450(CAM) and toluene dioxygenase. Cytochrome P450(CAM) catalyzed reductive dechlorinated reactions and toluene dioxygenase catalyzed oxidative dechlorination. With pentachloroethane, reductive dechlorination yielded trichloroethylene, which was further oxidized to formate and glyoxylate. The sequential action of cytochrome P450(CAM) and toluene dioxygenase with polyhalogenated compounds constitutes a novel engineered metabolic pathway.