M. Gut, T. Wilhelm, O. Beniston, S. Ogundipe, C.-C. Kuo, K. Nguyen, G. Lindemann, C. Atkins, A. Moyes, A. Furst
Massachusetts Institute of Technology (MIT),
United States
Keywords: bio-scaffolding, lanthanide recycling, lanmodulin, surface expression, rare earth element mining
Summary:
We present our investigation on utilizing freeze-dried scaffolded Lanmodulin (LanM) proteins expressed on the surface of E. coli for recovering rare earth elements (REEs) from unconventional sources of critical minerals. Rare earth elements (REEs) are essential to build electronic and electrical hardware.1 Yet, they are a limited resource currently obtained through carbon-intensive mining, necessitating substantial work to improve extraction and recycling technologies.2 To reduce the operational and environmental costs associated with REE recovery, microbes have been investigated as designed materials for REE adsorption.3,4 Here, bio-scaffolded Lanmodulin (LanM) proteins on the cell surface of E. coli serve as simple, effective materials for the recovery of REEs. Surface expression of the protein Lanmodulin (LanM) on E. coli using an ice-nucleation tag (INPNC), followed by freeze-drying of the microbes, yields a displayed protein material for REE recovery. Four REE cations (Y3+, La3+, Gd3+, and Tb3+) are captured efficiently, with over 80% binding even in the presence of competitive ions at one-hundred-fold excess. Moreover, these materials are readily integrated into a filter with high capture capacity (12 mg g-1 dry cell weight) for the selective isolation and recovery of REEs from complex matrices. Further, the proteins remain stable over ten bind-and-release cycles and a week of storage, demonstrating the potential of these materials to enable the sustainable recovery and recycling of lanthanides. Overall, the presented material can be prepared cost-effectively without requirements for protein purification or immobilization chemistries, significantly decreasing the potential cost of deployment.5 Applying this technology to mining and the development of a column-based system with optimized elution conditions that enable the selective recovery and release of these metals has the potential to significantly reduce the environmental impact of lanthanide recovery while ensuring a sufficient supply of these critical metals as demand continues to grow exponentially. (1) Cheisson, T.; Schelter, E. J. Rare Earth Elements: Mendeleev’s Bane, Modern Marvels. Science 2019, 363 (6426), 489–493. https://doi.org/10.1126/science.aau7628. (2) Daumann, L. J. A Natural Lanthanide-Binding Protein Facilitates Separation and Recovery of Rare Earth Elements. ACS Cent. Sci. 2021, 7 (11), 1780–1782. https://doi.org/10.1021/acscentsci.1c01247. (3) Park, D. M.; Reed, D. W.; Yung, M. C.; Eslamimanesh, A.; Lencka, M. M.; Anderko, A.; Fujita, Y.; Riman, R. E.; Navrotsky, A.; Jiao, Y. Bioadsorption of Rare Earth Elements through Cell Surface Display of Lanthanide Binding Tags. Environ. Sci. Technol. 2016, 50 (5), 2735–2742. https://doi.org/10.1021/acs.est.5b06129. (4) Hu, Q.-H.; Song, A.-M.; Gao, X.; Shi, Y.-Z.; Jiang, W.; Liang, R.-P.; Qiu, J.-D. Rationally Designed Nanotrap Structures for Efficient Separation of Rare Earth Elements over a Single Step. Nat. Commun. 2024, 15 (1), 1558. https://doi.org/10.1038/s41467-024-45810-1. (5) Gut, M.; Wilhelm, T.; Beniston, O.; Ogundipe, S.; Kuo, C.-C.; Nguyen, K.; Furst, A. Lanmodulin-Decorated Microbes for Efficient Lanthanide Recovery. Adv. Mater. 2025, n/a (n/a), 2412607. https://doi.org/10.1002/adma.202412607.