Metabolism of chlorofluorocarbons and polybrominated compounds by Pseudomonas putida G786(pHG-2) via an engineered metabolic pathway.
The recombinant bacterium Pseudomonas putida G786(pHG-2) metabolizes pentachloroethane to glyoxylate and carbon dioxide, using cytochrome P-450CAM and toluene dioxygenase to catalyze consecutive reductive and oxidative dehalogenation reactions (L.P. Wackett, M.J. Sadowsky, L.N. Newman, H.-G. Hur, and S. Li, Nature [London] 368:627-629, 1994). The present study investigated metabolism of brominated and chlorofluorocarbon compounds by the recombinant strain. Under anaerobic conditions, P. putida G786(pHG-2) reduced 1,1,2,2-tetrabromoethane, 1,2-dibromo-1,2-dichloroethane, and 1,1,1,2-tetrachloro-2,2-difluoroethane to products bearing fewer halogen substituents. Under aerobic conditions, P. putida G786(pHG-2) oxidized cis- and trans-1,2-dibromoethenes, 1,1-dichloro-2,2-difluoroethene, and 1,2-dichloro-1-fluoroethene. Several compounds were metabolized by sequential reductive and oxidative reactions via the constructed metabolic pathway. For example, 1,1,2,2-tetrabromoethane was reduced by cytochrome P-450CAM to 1,2-dibromoethenes, which were subsequently oxidized by toluene dioxygenase. The same pathway metabolized 1,1,1,2-tetrachloro-2,2-difluoroethane to oxalic acid as one of the final products. The results obtained in this study indicate that P. putida G786(pHG-2) metabolizes polyfluorinated, chlorinated, and brominated compounds and further demonstrates the value of using a knowledge of catabolic enzymes and recombinant DNA technology to construct useful metabolic pathways.
Hur
H G
HG
Department of Soil Science, University of Minnesota, St. Paul 55108.
Sadowsky
M J
MJ
Wackett
L P
LP
D000332:Aerobiosis; D000693:Anaerobiosis; D017402:Chlorofluorocarbons / Q000378:metabolism*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D006842:Hydrocarbons, Brominated / Q000378:metabolism*; D010105:Oxygenases / Q000378:metabolism; D016958:Pseudomonas putida / Q000201:enzymology / Q000378:metabolism*; D011995:Recombination, Genetic; D013045:Species Specificity
D017402:Chlorofluorocarbons; D006842:Hydrocarbons, Brominated; D003577:Cytochrome P-450 Enzyme System; D010105:Oxygenases; C023172:toluene dioxygenase