Pseudomonas sp. Cometabolizing Mixture of cis-DCE and TCE while Growing on Toluene in Soil Slurry

An indigenous Pseudomonas sp., isolated from the regional contaminated soil and identified as P.plecoglossicida, was evaluated for its aerobic cometabolic removal of cis-1,2-dichloroethylene (cis-DCE) and trichloroethylene (TCE) using toluene as growth substrate in a laboratory-scale soil slurry. The aerobic simultaneous bioremoval of the cis-DCE/TCE/toluene mixture was studied under different conditions. Results showed that the increased toluene concentration from 300 to 900 mg/kg increased the lag phase for the bacterial growth and correspondingly prolonged toluene bioremoval, while the bioremovalextent for cis-DCE, TCE,and toluenedeclined as the initial toluene concentration increased. In addition, the cometabolicbioremoval of cis-DCE and TCE was inhibited in the presence of hydrogen peroxide as the additional oxygen source, while the bioremoval of toluene (900 mg/kg) was enhanced. The subsequent addition of toluenedid not improve the cometabolicbioremoval of cis-DCE and TCE. The cometabolism ofcis-DCE and TCE was significantly greater when toluene was provided as growth substrate, compared to the BTEX mixture provided as substrates.