Biodegradation analyses of trichloroethylene (TCE) by bacteria and its use for biosensing of TCE

Trichloroethylene (ICE) is a toxic, recalcitrant groundwater pollutant. TCE-degrading microorganisms were isolated from various environments. The aerobic bacteria isolated from toluene- and tryptophan-containing media were Pseudomonas sp. strain ASA86 and Burkholderia sp. strain TAM17, respectively; these are necessary for inducing ICE biodegradation in a selective medium. The half-degradation time of ICE to a concentration of 1 mg/L was 18 h for strain ASA86 and 7 days for strain TAM17. While identifying toluene/TCE degradation genes, we found that in strain ASA86, the gene was the same as the todC1 gene product encoding toluene dioxygenase identified in Pseudomonas putida F1 and that in strain TAM17. the gene was similar to the tecA1 gene product encoding chlorobenzene dioxygenase identified in Burkholderia sp. P512. A novel ICE biosensor was developed using strain ASA86 as the inducer of toluene under aerobic conditions. The ICE biosensor exhibited a linear relationship below 3 ppm ICE. Detection limit of the biosensor was 0.05 ppm ICE. The response time of the biosensor was less than 10 min. The biosensor response displayed a constant level during a 2 day period. The ICE biosensor displayed sufficient sensitivity for monitoring ICE in environmental systems. (C) 2011 Elsevier B.V. All rights reserved.