title: Aerobic degradation of mixtures of tetrachloroethylene, trichloroethylene, dichloroethylenes, and vinyl chloride by toluene-o-xylene monooxygenase of Pseudomonas stutzeri OX1.
abstract: A recombinant strain of Escherichia coli (JM109/pBZ1260) expressing constitutively toluene-o-xylene monooxygenase (ToMO) of Pseudomonas stutzeri OX1 degraded binary mixtures (100 microM each) of tetrachloroethylene (PCE) with either trichloroethylene (TCE), 1,1-dichloroethylene (1,1-DCE), cis-dichloroethylene (cis-DCE), trans-1,2-dichloroethylene (trans-DCE), or vinyl chloride (VC). PCE degradation was 8-20% for these binary mixtures, while TCE and trans-DCE with PCE were degraded at 19%, 1,1-DCE at 37%, cis-DCE at 97%, and VC at 27%. The host P. stutzeri OXI was also found to degrade binary mixtures of PCE/TCE, PCE/cis-DCE, and PCE/VC when induced with toluene. Degradation of quaternary mixtures of PCE/TCE/trans-DCE/VC and PCE/TCE/cis-DCE/VC by JM109/pBZ1260 were also investigated as well as mixtures of PCE/TCE/trans-DCE/1,1-DCE/cis-DCE/VC; when all the chlorinated compounds were present, the best degradation occurred with 24-51% removal of each. For these degradation reactions, 39-85% of the stoichiometric chloride expected from complete degradation of the chlorinated ethenes was detected. The time course of PCE/TCE/1,1-DCE degradation was also measured for a mixture of 8, 17, and 6 microM, respectively; initial degradation rates were 0.015, 0.023. and 0.029 nmol/min x mg protein, respectively. This indicates that for the first time an aerobic enzyme can degrade mixtures of all chlorinated ethenes, including the once--so it was believed-completely recalcitrant PCE.
authors.affiliation: Department of Chemical Engineering, University of Connecticut, Storrs, 06269-3222, USA.
authors.forename: H
authors.initials: H
authors.lastname: Shim
authors.forename: D
authors.initials: D
authors.lastname: Ryoo
authors.forename: P
authors.initials: P
authors.lastname: Barbieri
authors.forename: T K
authors.initials: TK
authors.lastname: Wood
mesh_terms: D004000:Dichloroethylenes / Q000378:metabolism*; D010105:Oxygenases / Q000378:metabolism*; D011549:Pseudomonas / Q000201:enzymology*; D013750:Tetrachloroethylene / Q000378:metabolism*; D014241:Trichloroethylene / Q000378:metabolism*; D014752:Vinyl Chloride / Q000378:metabolism*
chemical_list: D004000:Dichloroethylenes; D014241:Trichloroethylene; D010105:Oxygenases; C114360:toluene 2-xylene monooxygenase; D013750:Tetrachloroethylene; D014752:Vinyl Chloride