Highlights
- Researchers discovered that rare earth elements (REEs) are biologically active metals essential to microbial life processes, challenging previous assumptions about their chemical inertness.
- Specific bacterial enzymes and proteins like LanM demonstrate high selectivity in rare earth element binding and separation, enabling potential bio-based extraction technologies.
- The study positions lanthanides as strategic bioelements with transformative potential in biomining, industrial recovery, and synthetic biology applications.
A groundbreaking review by Wenyu Yang and colleagues at Central South University, China (opens in a new tab), published in The ISME Journal (opens in a new tab) (January 2025), has charted the rapidly emerging frontier of rare earth element (REE) biology. It reveals key biomolecular roles for lanthanides in microbial metabolism and highlights their potential for environmentally sustainable REE extraction and separation.
The paper, titled “Emerging role of rare earth elements in biomolecular functions,” reviews a decade of discoveries showing that lanthanides are not only chemically strategic materials but also biologically active metals essential to microbial life processes. This finding disrupts traditional thinking that REEs are chemically inert in biology and points to a new class of bio-based REE separation tools.
REEs Are Biometals with Unique Enzymatic Functions
The review consolidates evidence that certain bacterial enzymes—particularly XoxF-type methanol dehydrogenases (MDH) and ExaF/PedH ethanol dehydrogenases (EDH)—require REEs like neodymium (Nd), lanthanum (La), or praseodymium (Pr) to function. These REE-dependent enzymes show higher catalytic activity and substrate affinity than their calcium-based counterparts.
Researchers also identified REE-binding proteins, most notably Lanmodulin (LanM) and Lanpepsy (LanP), which exhibit high selectivity and stability in REE coordination. LanM variants from different microbial species were able to distinguish between light and heavy REEs (LREEs vs. HREEs), enabling selective binding and potential for bio-based separation. In particular, Hans-Lan M demonstrated >98% selectivity for neodymium over dysprosium—an industry-grade separation level.
Bioseparation of REEs Moves Toward Reality
This research offers a biological blueprint for building cleaner, more efficient REE extraction systems, a critical need amid growing geopolitical and environmental concerns. Existing chemical separation relies on organic solvents, high energy input, and toxic waste, especially for separating chemically similar REEs. In contrast, REE-binding biomolecules could enable selective, low-energy, and biodegradable separation processes, which are ideal for urban mining, e-waste recycling, and wastewater recovery.
Already, LanM has been immobilized on agarose beads and magnetic nanoparticles for selective extraction from industrial samples. Engineered microbes, including E. coli and yeast strains displaying LanM on their surface, have also demonstrated proof-of-concept success in bioaccumulating REEs from mixed metal streams.
Regulatory Systems and Mechanisms Still Poorly Understood
Despite rapid progress, the authors highlight critical gaps in understanding how microorganisms transport, sense, and store REEs. While the LanM gene cluster appears central to REE uptake, regulation varies widely by species and environmental conditions. The intracellular purpose of REEs also remains uncertain beyond their known cofactor roles.
Moreover, few REE-binding proteins have resolved crystal structures, limiting the rational design of improved bioseparation tools. The biological pathways enabling REEs to cross membranes or bind selectively in complex environments require deeper biochemical mapping.
From Curiosity to Strategic Bioengineering Tool
Yang and co-authors argue that REEs must now be considered true bioelements, akin to iron or zinc, with real-world potential in biomining, industrial recovery, and synthetic biology. Their selective coordination by unique amino acid motifs (e.g., aspartate-rich EF-hand domains) makes them ideal candidates for protein engineering and synthetic separation systems.
With global REE demand skyrocketing—especially for Nd and Dy in EVs, wind turbines, and defense—biological solutions could revolutionize the industry, offering cleaner, scalable alternatives to solvent-heavy hydrometallurgy. The field remains in early stages, but its trajectory mirrors the rise of biotech in heavy metal recovery two decades ago.
The National Natural Science Foundation of China and the Hunan Province Innovation Program funded the study. The authors disclose no conflicts.
Citation
Yang W, Wu K, Chen H, Huang J, Yu Z. Emerging role of rare earth elements in biomolecular functions. The ISME Journal, Volume 19, Issue 1, January 2025. DOI: 10.1093/ismejo/wrae241 (opens in a new tab)
Leave a Reply