Oxidation of Trichloroethylene, 1,1-Dichloroethylene, and Chloroform by Toluene/ o -Xylene Monooxygenase from Pseudomonas stutzeri OX1

Abstract

ABSTRACT Toluene/ o -xylene monooxygenase (ToMO) from Pseudomonas stutzeri OX1, which oxidizes toluene and o -xylene, was examined for its ability to degrade the environmental pollutants trichloroethylene (TCE), 1,1-dichloroethylene (1,1-DCE), cis -1,2-DCE, trans -1,2-DCE, chloroform, dichloromethane, phenol, 2,4-dichlorophenol, 2,4,5-trichlorophenol, 2,4,6-trichlorophenol, 2,3,5,6-tetrachlorophenol, and 2,3,4,5,6-pentachlorophenol. Escherichia coli JM109 that expressed ToMO from genes on plasmid pBZ1260 under control of the lac promoter degraded TCE (3.3 μM), 1,1-DCE (1.25 μM), and chloroform (6.3 μM) at initial rates of 3.1, 3.6, and 1.6 nmol/(min · mg of protein), respectively. Stoichiometric amounts of chloride release were seen, indicating mineralization (2.6, 1.5, and 2.3 Cl − atoms per molecule of TCE, 1,1-DCE, and chloroform, respectively). Thus, the substrate range of ToMO is extended to include aliphatic chlorinated compounds.