Microorganisms that biosynthesize broad-specificity oxygenases to initiate metabolism of linear and branched-chain alkanes, nitroalkanes, cyclic ketones, alkenoic acids, and chromenes were surveyed for the ability to biodegrade trichloroethylene (TCE). The results indicated that TCE oxidation is not a common property of broad-specificity microbial oxygenases. Bacteria that contained nitropropane dioxygenase, cyclohexanone monooxygenase, cytochrome P-450 monooxygenases, 4-methoxybenzoate monooxygenase, and hexane monooxygenase did not degrade TCE. However, one new unique class of microorganisms removed TCE from incubation mixtures. Five Mycobacterium strains that were grown on propane as the sole source of carbon and energy degraded TCE. Mycobacterium vaccae JOB5 degraded TCE more rapidly and to a greater extent than the four other propane-oxidizing bacteria. At a starting concentration of 20 ,uM, it removed up to 99% of the TCE in 24 h. M. vaccae JOB5 also biodegraded 1,1-dichloroethylene, trans-1,2-dichloroethylene, cis-1,2-dichloroethylene, and vinyl chloride.

Trichloroethylene was metabolically activated by toluene dioxygenase to produce toxic effects in Pseudomonas putida Fl. Cytotoxicity was indicated by growth inhibition and by the covalent modification of cellular molecules in P. putida Fl exposed to ['4C]trichloroethylene. With a toluene dioxygenase mutant, neither growth inhibition nor alkylation of intracellular molecules was observed.