Enhancing cadmium biosorption capacity in E. coli through heterologous expression of metal-chelating proteins: Insights into bioremediation potential and mechanisms

Cadmium (Cd) is a biologically non-essential and toxic heavy metal that enters the environment through natural emissions or anthropogenic activities, posing threats to human health. The efficient expression of metal-chelating proteins (MCP) in microorganisms can enhance microbial remediation of Cd. In this study, a heterologous expression system (GEM01) of MCP encoded by the mcp gene in E. coli was constructed, and the adsorption effect and potential mechanism on Cd were explored. The results indicated that Cd2+ significantly enhanced the abundance of mcp gene in GEM01, thus increasing the Cd2+ biosorption capacity (8.09 mg/g, 2.32 times higher than the control). The retention of Cd2+ during the autolysis of GEM01 was 87.87