Virus-Based Thermoresponsive Separation of Rare-Earth Elements
Although rare-earth elements (REEs) are not very rare, their recovery and purification is very cumbersome, with no significant concentrations that would help with mining. This does contribute to limiting their availability, but there might be more efficient ways to recover these REEs. One such method involves the use of a bacteriophage that has been genetically modified to bind to specific REEs and release them based on thermal conditions.
The primary research article in Nano Letters is sadly paywalled, but the supporting information PDF gives some details. We can also look at the preceding article (full PDF) by [Inseok Chae] et al. in Nano Letters from 2024, in which they cover the binding part using a lanthanide-binding peptide (LBP) that was adapted from Methylobacterium extorquens.
With the new research an elastin-like peptide (ELP) was added that has thermoresponsive responsive properties, allowing the triggering of coacervation after the phages have had some time in the aqueous REE containing solution. The resulting slurry makes it fairly easy to separate the phages from the collected REE ions, with the phages ready for another cycle afterwards. Creating more of these modified phages is also straightforward, with the papers showing the infecting of E. coli to multiply the phages.
Whether the recovery rate and ability to scale makes it an economically feasible method of REE recovery remains to be seen, but it’s definitely another fascinating use of existing biology for new purposes.