Response of bioluminescent bacteria to sixteen azo dyes

Recombinant bioluminescent bacteria were used to monitor and classify the toxicity of azo dyes. Two constitutive bioluminescent bacteria, Photobacterium phosphoreum and Escherichia coli, E. coli GC2 (lac::luxCDABE), were used to detect the cellular toxicity of the azo dyes. In addition, four stress-inducible bioluminescent E. coli, DPD2794 (recA::luxCDABE), a DNA damage sensitive strain; DPD2540 (fabA::luxCDABE), a membrane damage sensitive strain; DPD2511 (katG::luxCDABE), an oxidative damage sensitive strain; and TV1061 (grpE::luxCDABE), a protein damage sensitive strain, were used to provide information about the type of toxicity caused by crystal violet, the most toxic dye of the 16 azo dyes tested. These results suggest that azo dyes result in serious cellular toxicity in bacteria, and that toxicity monitoring and classification of some azo dyes, in the field, may be possible using these recombinant bioluminescent bacteria.