Entirely recombinant protein-based hydrogels for selective heavy metal sequestration

Abstract

Materials that can adsorb heavy metal ions with high efficiency and selectivity hold great promise for green mining and environmental remediation. Here we present a strategy for synthesizing hydrogel-based heavy metal adsorbents under mild physiological conditions by covalently stitching together metalloproteins such as engineered super uranyl-binding proteins (SUP) and naturally occurring molybdate/chromate binding proteins (ModA). The resulting recombinant protein-based hydrogels showed the ability to selectively sequester uranyl from seawater and chromate from tap water, respectively. These results point to a convenient and versatile approach for converting metalloproteins to macroscopic metal adsorbents with huge potential in alternative energies as well as heavy metal remediation.