Design, construction, and characterization of a set of biosensors for aromatic compounds

Aromatic pollutants in the environments pose significant threat to human health due to their persistence and toxicity. Here, we report the design and comprehensive characterization of a set of aromatic biosensors constructed using green fluorescence protein as the reporter and aromatics-responsive transcriptional regulators, namely, NahR, XylS, HbpR, and DmpR, as the detectors. The genetic connections between the detectors and the reporter were carefully adjusted to achieve fold inductions far exceeding those reported in previous studies. For each biosensor, the functional characteristics including the dose-responses, dynamic range, and the detection spectrum of aromatic species were thoroughly measured. In particular, the interferences that nontypical inducers exert on each biosensor's response to its strongest inducer were evaluated. These well-characterized biosensors might serve as potent tools for environmental monitoring as well as quantitative gene regulation.