Selective Rare Earth Recovery Employing Filamentous Viruses with Chemically Conjugated Peptides

Abstract Selective recovery of rare earth elements from industrial waste is essential for recycling processes and a green economy. Here, we developed a filamentous virus (phage)‐based selective recovery system for neodymium ions (Nd 3+ ), which are generally used in common rare earth magnets composed of neodymium‐iron‐boron alloys. Affinity‐dependent peptide screening against Nd 3+ produced phage clones displaying peptides with a specific affinity for Nd 3+ . Binding analyses revealed that the peptide had a specific affinity for Nd 3+ rather than Fe 3+ . Structural analyses of the peptide showed that when the peptide bound to Nd 3+ , it underwent a structural transition from random‐coil to β ‐turn structures, resulting in specific affinity for Nd 3+ . Approximately 6 times more Nd 3+ adsorbed onto the peptide‐modified phage than Fe 3+ from a mixed solution containing Nd 3+ and excess Fe 3+ , demonstrating that suitably modified phages with Nd 3+ ‐binding peptides can act as a selective recovery scaffold for Nd 3+ .