Engineered cells for selective detection and remediation of Hg2+ based on transcription factor MerR regulated cell surface displayed systems

Mercury pollution has been one of the most serious environmental problems today. The detection and remediation of mercury contamination are of special concern due to its nondegradable nature, bioaccumulation effect, and significant toxicity. In this research, the whole-cell based detection and remediation systems for Hg 2+ were engineered based on the cell surface engineering technique and transcriptional activation mechanism of metalloprotein MerR. The engineered biodetection system showed high selectivity for Hg 2+ over other metal ions with the detection limit as low as 0.1 nM. It also permitted a rapid, visual, and on-site detection of bioavailable Hg 2+ for large-scale water samples with simple processes. The engineered bioremediation system, which was more efficient than the most current biosystems with limited adsorption capacities, could continuously reduce mercury contamination in wide concentration by transforming highly toxic Hg 2+ to volatile and much less deleterious Hg 0 with extraordinary selectivity. In addition, the bioremediation system could perform function in the absence of extra inductive agent and showed an increased protection of cells against Hg 2+ biotoxicity. By fully imitating and utilizing the microorganisms, the engineered biochemical systems have great potential in the practical application of detecting and remediating Hg 2+ in the contaminated aquatic systems.