An engineered quorum-sensing-based whole-cell biosensor for active degradation of organophosphates

The environmental accumulation of organophosphates is a serious threat to public health. To detect these xenobiotics, a broad range of sensors has been developed in past decades. However, sensors with high sensitivity and a capability for degrading organophosphates are rare. In this study, "smart" whole-cell biosensors were created by combining synthetic biology approaches with the bacterial quorum sensing (QS) mechanism. The engineered whole-cell biosensor pUC57-QS-DSF-F42 L/E coli DH5α can sense a wide array of phenolic compounds including phenol and p-nitrophenol (p-NP). By optimizing the genetic circuits, the phenol and p-NP detection limits reached 0.1 and 1 μM, respectively. Importantly, by replacing the fluorescence-generated reporter sfGFP with MP-degrading enzyme PoOPH_M2, the whole-cell biosensor pUC57-OPH-QS-DSF-F42 L/E coli DH5α actively degraded 10 and 100 μM methyl parathion (MP), a typical organophosphate pesticide, which was artificially added to the cell culture at different time points in five consecutive degrading experiments, demonstrating its MP sensing and degrading capabilities. The universal design of this new biosensor can be used to create more efficient biosensors to detect and degrade various pollutants in the environment for rapid testing and bioremediation.