Mercury is a poisonous heavy metal that poses a threat to aquatic life and humans. Recently, increasing attention has been paid to mercury remediation and its detection in the environment by biological technology. In our project, a series of mercury-specific binding peptide termed metal catcher (MC), which has a high affinity and selectivity toward mercury, was examined. The subsequent IC and GFP were fused and displayed on Escherichia coli cell surface by using an N-terminal region ice nucleation protein anchor.
Whole-cell sorbents of construction facilitated selective adsorption of mercury ions from a solution containing different heavy metal ions and detection mercury and cooper. The MC aided rapid detection of copper, mercury, and cadmium in 2 min with a low detection limit (1 uM).Additionally, mercury levels were reduced by approximately 36% by using the MC. The transformant strains were then fed to Cyprinus carpio and colonized in the microbiota. C. carpio with transformants showed significantly lower accumulation of heavy metals compared to the control group. The control group was E. coli BL21 containing a pET23b plasmid without any exogenous gene. Moreover, the metal remediation ability of the microbiota with transformants was improved by Illumina MiSeq 16S rRNA amplicon sequencing. The surface-engineered E. coli effectively protected fish from the toxicity of mercury ions at high concentrations in an aquatic environment. Thus, gut remediation is an ideal approach to control heavy metal contamination in fish.