A Bioluminescent Whole-Cell Reporter for Detection of 2,4-Dichlorophenoxyacetic Acid and 2,4-Dichlorophenol in Soil

Abstract

ABSTRACT A bioreporter was made containing a tfdRP DII -luxCDABE fusion in a modified mini-Tn 5 construct. When it was introduced into the chromosome of Ralstonia eutropha JMP134, the resulting strain, JMP134-32, produced a sensitive bioluminescent response to 2,4-dichlorophenoxyacetic acid (2,4-D) at concentrations of 2.0 μM to 5.0 mM. This response was linear ( R 2 = 0.9825) in the range of 2.0 μM to 1.1 × 10 2 μM. Saturation occurred at higher concentrations, with maximal bioluminescence occurring in the presence of approximately 1.2 mM 2,4-D. A sensitive response was also recorded in the presence of 2,4-dichlorophenol at concentrations below 1.1 × 10 2 μM; however, only a limited bioluminescent response was recorded in the presence of 3-chlorobenzoic acid at concentrations below 1.0 mM. A significant bioluminescent response was also recorded when strain JMP134-32 was incubated with soils containing aged 2,4-D residues.