Virus-Based Thermoresponsive Separation of Rare-Earth Elements

Rare-earth elements (REEs) are essential to clean energy, defense, and advanced electronics, yet their separation remains environmentally intensive due to the chemical similarity among REEs and reliance on harsh separation conditions. Here, we report a genetically engineered, virus-based platform for selective and scalable REE recovery under aqueous conditions through temperature modulation. By codisplaying a lanthanide-binding peptide (LBP) derived from Lanmodulin found in <i>Methylobacterium extorquens</i> and a thermoresponsive elastin-like peptide (ELP) on the major coat proteins of filamentous bacteriophage, we constructed a bifunctional biotemplate that enables temperature-triggered coacervation and selective REE separation. The LBP confers preferential affinity for heavy REEs (HREEs) over light REEs (LREEs), allowing for internal REE fractionation, while ELP-mediated phase transition enables thermoresponsive REE separation. This biomolecular process is recyclable, retaining metal selectivity over multiple cycles. The modularity of the platform supports adaptation to other metal targets, offering a sustainable and tunable strategy for next-generation hydrometallurgy.