CHLOROFORM MINERALIZATION BY TOLUENE-OXIDIZING BACTERIA

Seven toluene-oxidizing bacterial strains (Pseudomonas mendocina KR1, Burkholderia cepacia G4, Pseudomonas putida F1, Pseudomonas pickettii PKO1, and Pseudomonas sp, strains ENVPC5, ENVBF1, and ENV113) were tes ted for their ability to degrade chloroform (CF). The greatest rate of CF oxidation was achieved with strain ENVBF1 (1.9 nmol/min/mg of cell protein). CF also was oxidized by P. mendocina KR1 (0.48 nmol/min/mg of cell protein), strain ENVPC5 (0.49 nmol/min/mg of cell protein), an d Escherichia coli DH510B(pRS202), which contained cloned toluene 4-mo nooxygenase genes from P. mendocina KR1 (0.16 nmol/min/mg of cell prot ein), Degradation of [C-14]CF and ion analysis of culture extracts rev ealed that CF was mineralized to CO2 (similar to 30 to 57% of the tota l products), soluble metabolites (similar to 15%), a total carbon frac tion irreversibly bound to particulate cellular constituents (similar to 30%), and chloride ions (similar to 75% of the expected yield), CF oxidation by each strain was inhibited in the presence of trichloroeth ylene, and acetylene significantly inhibited trichloroethylene oxidati on by P. mendocina KR1, Differences in the abilities of the CF-oxidizi ng strains to degrade other halogenated compounds were also identified . CF was not degraded by B. cepacia G4, P. putida F1, P. pickettii PKO 1, Pseudomonas sp. strain ENV113, or P. mendocina KRMT, which contains a tmo mutation.