Aerobic degradation of mixtures of tetrachloroethylene, trichloroethylene,dichloroethylenes, and vinyl chloride by toluene-o-xylene monooxygenase ofPseudomonas stutzeri OX1

A recombinant strain of Escherichia coli (JM109/pBZ1260) expressing constit utively toluene-o-xylene monooxygenase (ToMO) of Pseudomonas stutzeri OX1 d egraded binary mixtures (100 muM each) of tetrachloroethylene (PCE) with ei ther trichloroethylene (TCE), 1,1-dichloroethylene (1,1-DCE), cis-dichloroe thylene (cis-DCE), trans-1,2-dichloroethylene (trans-DCE), or vinyl chlorid e (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%, an d VC at 27%. The host P. stutzeri OX1 was also found to degrade binary mixt ures of PCE/TCE, PCE/cis-DCE, and PCE/VC when induced with toluene. Degrada tion 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/tran s-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 degrad ation reactions, 39-85% of the stoichiometric chloride expected from comple te 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 muM, respectively; initial degradation rates were 0.015, 0.023, and 0.029 nmol/min.mg protein, respectively. This indicates that for the first time a n aerobic enzyme can degrade mixtures of all chlorinated ethenes, including the once - so it was believed completely recalcitrant PCE.