Programmable and low-cost biohybrid membrane for efficient heavy metal removal from water

Abstract

Heavy metal pollution in rivers and lakes from industrial development poses great challenges to environmental remediation, especially of low-concentration metal ions. Current technologies for removing low-concentration heavy metal ions are typically expensive, and there is therefore an urgent need to develop new strategies. Low-cost microbial amyloid nanofibers (MAN) have demonstrated excellent abilities in removing heavy metal ions. In this study, we used synthetic biology strategies to design programmable MAN in silico and create artificial MAN for biohybrid membrane preparation. It was found that MAN could be largely produced and self-assembled, and it exhibited a removal rate of more than 98 % for 50 mg/L lead ions. Furthermore, genetic edits of MAN with functional peptides endowed the specific binding ability to heavy metals even at 1 mg/L. Impressively, biohybrid membranes using activated carbon as the supporting material based on programmable MAN showed long lifecycles and low costs in scale-up water purification systems. This study provides a programmable and low-cost strategy for the efficient treatment of heavy metal wastewater.