AEROBIC MINERALIZATION OF TRICHLOROETHYLENE, VINYL-CHLORIDE, AND AROMATIC-COMPOUNDS BY RHODOCOCCUS SPECIES

Two Rhodococcus strains which were isolated from a trichloroethylene ( TCE)-degrading bacterial mixture and Rhodococcus rhodochrous ATCC 2119 7 mineralized vinyl chloride (VC) and TCE. Greater than 99.9% of a 1-m g/liter concentration of VC was degraded by cell suspensions. [1,2-C-1 4]VC was degraded by cell suspensions, with the production of greater than 66% (CO2)-C-14 and 20% C-14-aqueous phase products and incorporat ion of 10% of the C-14 into the biomass. Cultures that utilized propan e as a substrate were able to mineralize greater than 28% of [1,2-C-14 ]TCE to (CO2)-C-14, with approximately 40% appearing in C-14-aqueous p hase products and another 10% of C-14 incorporated into the biomass. V C degradation was oxygen dependent and occurred at a pH range of 5 to 10 and temperatures of 4 to 35 degrees C. Cell suspensions degraded up to 5 mg of TCE per liter and up to 40 mg of VC per liter. Propane com petitively inhibited TCE degradation. Resting cell suspensions also de graded other chlorinated aliphatic hydrocarbons, such as chloroform, 1 ,1-dichloroethylene, and 1,1,1-trichloroethane. The isolates degraded a mixture of aromatic and chlorinated aliphatic solvents and utilized benzene, toluene, sodium benzoate, naphthalene, biphenyl, and n-alkane s ranging in size from propane to hexadecane as carbon and energy sour ces. The environmental isolates appeared more catabolically versatile than R. rhodochrous ATCC 21197. The data report that environmental iso lates of Rhodococcus species and R. rhodochrous ATCC 21197 have the po tential to degrade TCE and VC in addition to a variety of aromatic and chlorinated aliphatic compounds either individually or in mixtures.