Lanmodulin‐Decorated Microbes for Efficient Lanthanide Recovery

Abstract

Rare earth elements (REEs) are essential for many clean energy technologies.Yet, they are a limited resource currently obtained through carbon-intensivemining. Here, bio-scaffolded proteins serve as simple, effective materials forthe recovery of REEs. Surface expression of the protein lanmodulin (LanM) onE. coli, followed by freeze-drying of the microbes, yields a displayed proteinmaterial for REE recovery. Four REE cations (Y3+, La 3+, Gd3+, and Tb3+) arecaptured efficiently, with over 80% recovery even in the presence ofcompetitive ions at one-hundred-fold excess. Moreover, these materials arereadily integrated into a filter with high capture capacity (12 mg g−1 dry cellweight) for the selective isolation and recovery of REEs from complexmatrices. Further, the proteins in the filter remain stable over tenbind-and-release cycles and a week of storage. To improve the deployability ofthis filter material, a simple colorimetric assay with the dyealizarin-3-methyliminodiacetic acid is incorporated. The assay can beperformed in under 5 min, enabling rapid monitoring of REE recovery andfilter efficiency. Overall, this low-cost, robust material will enableenvironmentally friendly recycling and recovery of critical elements.