Analysis of Bioavailable Toluene by Using Recombinant Luminescent Bacterial Biosensors with Different Promoters

Abstract

In this study, we constructed recombinant luminescent Escherichia coli with T7, T3, and SP6 promoters inserted between tol and lux genes as toluene biosensors and evaluated their sensitivity, selectivity, and specificity for measuring bioavailable toluene in groundwater and river water. The luminescence intensity of each biosensor depended on temperature, incubation time, ionic strength, and concentrations of toluene and coexisting organic compounds. Toluene induced the highest luminescence intensity in recombinant lux-expressing E. coli with the T7 promoter [T7-lux-E. coli, limit of detection (LOD) = 0.05 μM], followed by that in E. coli with the T3 promoter (T3-lux-E. coli, LOD = 0.2 μM) and SP6 promoter (SP6-lux-E. coli, LOD = 0.5 μM). Luminescence may have been synergistically or antagonistically affected by coexisting organic compounds other than toluene; nevertheless, low concentrations of benzoate and toluene analogs had no such effect. In reproducibility experiments, the biosensors had low relative standard deviation (4.3%–5.8%). SP6-lux-E. coli demonstrated high adaptability to environmental interference. T7-lux-E. coli biosensor—with low LOD, wide measurement range (0.05–500 μM), and acceptable deviation (−14.3% to 9.1%)—is an efficient toluene biosensor. This is the first study evaluating recombinant lux E. coli with different promoters for their potential application in toluene measurement in actual water bodies.

Emerging bioremediation technologies for the treatment of textile wastewater containing synthetic dyes: a comprehensive review

“…To create GMOs, functional genes from Sphingomonas desiccabilis, Escherichia coli, Bacillus idriensis, Pseudomonas putida, Mycobacterium marinum, Ralstoniaeutropha, and other bacteria strains were employed and transferred into other species. 121 This method is useful for the degradation of various chlorobenzene acids, 122 toluene, 123 halogenated pesticides, 124 and toxic wastes. 125 However, dye degradation studies using this method are scarcely available in the literature.…”