An interesting feature of these adsorption systems is that the expression of the chimeric OmpC with the metal binding site is induced by heavy metals (Table 1). Hence, the construction of a heavy metal biosensor in combination with a bio-adsorption system would complement analytical heavy metal detection methodologies and enable the rapid monitoring and removal of toxic levels of bioavailable metal contaminants in industrial settings. The above biosensor combined with bio-adsorption was able to absorb heavy metals efficiently without any induction system. Following this scheme, this synthetic bacterial system is an excellent paradigm for developing multifunctional synthetic systems that can be applied both in the efficient removal and recovery of the target compound.Table 1Two-component regulatory systems based on microbial biosensors coupled with bio-adsorptionField of applicationTCRSFunctionHost chassisPromoter-reporterChemical targetDetection range (mM)ReferencesBioremediationZraSR (also known as HydHG) Biosensor E. coli XL1-blue zraP-gfp-HydGZinc0.01–1CuSRBiosensor E. coli XL1-blue cusC-gfp-CusRCopper0.004–1ZraSR and CusSRBiosensor coupled with bio-adsorption E. coli XL1-blue zraP-gfp, cusC-gfp Zinc and Copper0.05–1ZraSRBiosensor coupled with bio-adsorption E. coli TOP10 zraP-gfp-ompC Lead0.3–1ZraSR Biosensor coupled with bio-adsorption E. coli XL1-blue zraP-gfp Zinc0.1–1BiorefineryDcuSZ (Chimeric)Biosensor E. coli BL21(DE3) ompC-gfp Fumarate0.1–10MalKZ (Chimeric)Biosensor E. coli BL21(DE3) ompC-gfp Malate0.1–10AauSZ (Chimeric)Biosensor E. coli BL21(DE3) ompC-gfp Acidic amino acid0.05–10Tazl (Chimeric)Biosensor E. coli RU1012 ompC-lacZ Aspartate0.2–1