Highlights

• VCU's Dr. Leah Spangler developed S824, a synthetic protein that selectively binds rare earth elements in water at room temperature without harsh chemicals, offering a cleaner alternative to conventional extraction methods that require hundreds of toxic solvent-heavy processing steps.
• The technology addresses a critical U.S. supply chain vulnerability, as China controls 60-70% of global rare earth processing and building domestic capacity would take 15-20 years using traditional methods that face environmental pushback and lack private investment.
• Spangler co-founded BioRe-Element Technologies with support from DARPA and VCU's Commercialization Fund to scale the protein-based separation process, testing reusability and industrial viability to make domestic rare earth processing economically and environmentally sustainable.

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Rare earth elements sit at the heart of modern technology. They make electric vehicle motors spin, wind turbines generate power, smartphones vibrate, and MRI machines produce the images that save lives. Yet despite their importance, the process of separating and purifying these metals has remained stubbornly dirty, energy-intensive, and concentrated overseas. A researcher at Virginia Commonwealth University is working to change that, not with bigger chemical plants, but with a tiny, purpose-built protein.

Leah Spangler, Ph.D., (opens in a new tab) an assistant professor in VCU's Department of Chemical and Life Science Engineering, has developed a synthetic protein called S824 that can selectively latch onto specific rare earth elements in water at room temperature, without the harsh solvents and acids that define conventional extraction.

The work, supported by both the Defense Advanced Research Projects Agency (DARPA) and VCU TechTransfer and Ventures' Commercialization Fund, represents a fundamentally different approach to a problem that has dogged the mining and materials industries for decades.

Leah Spangler, PhD

Why Rare Earths Are So Hard to Separate

The seventeen rare earth elements, a group that includes neodymium, dysprosium, terbium, and gadolinium, share remarkably similar chemical properties. That similarity is exactly what makes them so difficult to pull apart from one another. Traditional separation involves passing crushed ore through hundreds of solvent-heavy processing steps, each one nudging a slightly different element out of the mixture. These conventional practices require large amounts of toxic chemicals like kerosene and phosphonates, and the process can stretch across dozens or even hundreds of individual stages. The result is enormous volumes of toxic chemical waste, huge energy costs, and a process so expensive and environmentally damaging that most Western nations have ceded it almost entirely to overseas producers.

China currently dominates global rare earth processing, handling roughly 60 to 70 percent of the world's supply chain. That concentration has become a strategic vulnerability. According to the Chicago Council on Global Affairs, the time horizon to build out the U.S. supply chain remains at 15 to 20 years, and that timeline is not made shorter by tariffs, executive orders, or international mineral agreements. Processing plants are expensive, lack the backing of private investment, will create pushback from communities due to environmental impact, and require long lead times to come online. Meanwhile, the Mountain Pass Mine in California remains the only major operational domestic source, with emerging sites in Wyoming, Alaska, and Texas still years from full production. Building cleaner, economically viable separation facilities at home requires new technology, not just new mines.

Engineering a Protein from Scratch

Spangler's approach begins at the molecular level. S824 is what scientists call a "de novo" protein, designed from amino acid building blocks rather than borrowed from nature. Unlike proteins shaped by millions of years of evolution to perform biological tasks, S824 was deliberately engineered with one goal in mind: to grab certain rare earth elements and ignore everything else.

The protein's selectivity is its most striking feature. When exposed to a mixture containing rare earth elements alongside common metals like copper, zinc, and calcium, S824 binds preferentially to the higher-value rare earths, including terbium, dysprosium, and gadolinium, while leaving the other metals behind. This specificity is crucial because real-world ore and mining waste streams contain a messy cocktail of different metals, and any practical separation technology must be able to distinguish between them reliably.

Equally important is where and how the protein operates. S824 works in water at room temperature. There is no need for the concentrated acids, organic solvents, or high-temperature reactors that conventional processing demands. And the protein remains stable under the acidic conditions typically found in mining waste streams, meaning it can function in the kinds of environments where it would actually need to be deployed.

Spangler's DARPA-funded work also explores an additional capability: engineering proteins that can be triggered by light to release bound rare earth elements on demand. This level of control would add another dimension to the separation process, allowing operators to capture and release specific metals with precision timing.

The Environmental and Economic Stakes

The environmental case for a cleaner separation method is well documented. According to researchers at the University of Pennsylvania's Kleinman Center for Energy Policy, the refineries required to process critical minerals generate significant environmental hazards, including strong acids such as hydrofluoric and sulfuric acid, radioactive elements like thorium and uranium, and heavy metals including cadmium, lead, and arsenic. These byproducts stress local water resources and threaten surrounding communities. A protein-based approach that operates in water without harsh chemicals could dramatically reduce that footprint.

The economic argument is equally compelling. The hundreds of sequential extraction steps in conventional processing translate directly into high capital and operating costs. A biological separation method that achieves selectivity in fewer steps could lower the barrier to building domestic processing capacity. If the United States and other nations want to reduce their dependence on foreign supply chains for critical minerals, they need technologies that make local production financially viable, not just technically possible.

Rare earth elements are also increasingly important in the global transition away from fossil fuels. Neodymium and dysprosium are essential for the permanent magnets in electric vehicle motors and wind turbine generators. Terbium plays a role in energy-efficient lighting. Gadolinium is used in medical imaging. As climate policy drives adoption of clean energy technologies, demand for these elements is projected to grow substantially in the coming decades, making the need for sustainable sourcing more urgent.

From Lab Bench to Market

Spangler is not content to leave S824 as a laboratory curiosity. She recently co-founded BioRe-Element Technologies, a company aimed at advancing the protein-based separation method toward commercial use. The next phase of development involves testing S824 in chromatography-style columns, essentially running mining waste solutions through columns packed with the protein, to measure how efficiently it captures target elements, how many cycles it can endure before degrading, and what the economics of scaling up would look like.

These are the questions that separate a promising research result from a viable industrial process. Reusability matters because the protein must work not just once but thousands of times to be cost-effective. Scalability matters because mining operations deal in large volumes. And capture efficiency matters because even small improvements in selectivity can translate into significant economic and environmental gains atindustrial scale.

The Commercialization Fund award from VCU TechTransfer and Ventures is designed precisely to bridge this gap between academic research and real-world application. It provides two years of support, with funding awarded twice yearly, to help campus researchers move their innovations toward market readiness.

A Broader Shift in Thinking

Spangler's work is part of a broader movement in materials science and chemical engineering that turns to biology for solutions to industrial problems. Researchers at Penn State University have demonstrated that a naturally occurring bacterial protein called lanmodulin is over 100 million times better at binding lanthanides compared to common metals like calcium, and can separate similar rare earth metals from one another quickly and efficiently at room temperature. At UC Berkeley, scientists have genetically engineered a harmless virus to act as a biosorbent that grabs rare earth metals from water and releases them with gentle changes in temperature and acidity. These parallel efforts, alongside Spangler's synthetic protein work at VCU, point toward a future where biology replaces brute-force chemistry in critical mineral processing.

In the case of rare earth separation, the conventional approach is essentially brute force: throw enough solvent at the problem and eventually the elements will sort themselves out. A protein like S824 offers something closer to a surgical instrument, precise, efficient, and gentle. Whether that precision can be maintained at an industrial scale remains to be proven, but the early results suggest a path worth pursuing.

As nations race to secure reliable supplies of the elements that underpin modern technology and the clean energy transition, innovations like S824 offer a reminder that sometimes the most powerful tools are also the smallest.

Sources:

• VCU Engineering: Rare Earth Elements Research Receiving New Awards (opens in a new tab)
• VCU Engineering: DARPA Funds Eco-Friendly Rare Earth Purification Research (opens in a new tab)
• Chicago Council on Global Affairs: Critical Minerals and Rare Earth Elements Challenges (opens in a new tab)
• Kleinman Center for Energy Policy: Rare Earth Elements Pose Environmental, Economic Risks (opens in a new tab)
• Penn State University: A Protein Mines and Sorts Rare Earths (opens in a new tab)
• UC Berkeley Engineering: Greener Way to Extract Rare Earth Elements (opens in a new tab)
• Spangler Lab, Virginia Commonwealth University (opens in a new tab)