Repeated Recovery of Rare Earth Elements Using a Highly Selective and Thermo‐Responsive Genetically Encoded Polypeptide

Abstract

Rare earth elements (REEs) have become increasingly important materials owing to their use in the high-tech and clean-energy industries. However, the unpredictable supply, possible health risks, and environmentally unsustainable extraction practices associated with REEs have encouraged the development of green technologies for the selective extraction and recovery of metals. This study presents a simple and innovative approach for the selective extraction and recovery of total REEs. Elastin-like polypeptide (ELP) and the REE-binding domain (lanmodulin) are fused to form REEs-sensitive and thermo-responsive genetically encoded ELP called RELP, where ELP offered a reversible, inverse phase transition for repeated uses. The RELP are purified and used for the selective extraction of total REEs from competing non-REEs metals by controlling the solution temperature (4 and 37 °C) and pH. RELP exhibit high REE specificity, even in the presence of non-REE metal ions. The bound REEs are readily recovered during at least six repeated cycles, and the efficiency is maintained. Moreover, REEs are selectively recovered by RELP from steel slag leachate, a potential industrial source of REEs. RELP offers a rapid, selective, and scalable method for REE extraction and recovery. This technology can be adapted to recover other precious metals and commodities.

Engineering lanmodulin's selectivity for actinides over lanthanides by controlling solvent coordination and second-sphere interactions

“…LanM can selectively scavenge Ln 3+ ions even in the presence of billons of equivalents of competing metal ions, and its complexes remain stable as low as pH $2.5 and at least up to 95 C. 33,35,48 It allows for selective recovery of rare earths from lowgrade industrial feedstocks, 48 or for detection of nanomolar concentrations of lanthanides in highly complex matrices, 35,52 or even for lanthanide-lanthanide separation using immobilized LanM. 7 In line with our results, Hussain et al 53 recently leveraged the thermal stability of LanM to recover lanthanides from steel slag leachates using a biomaterial based on LanM and an elastinlike polypeptide via heat-induced precipitation cycles. Furthermore, our team demonstrated 54 that LanM is even more effective at binding trivalent actinides, capable of scavenging actinium (Ac 3+ ) down to femtomolar concentrations while remaining selective against radium (Ra 2+ ) or even >10 +10 equivalents of endogenous cations (e.g., Ca 2+ , Mg 2+ , Cu 2+ , Zn 2+ , Mn 2+ ).…”

Lanmodulin-Functionalized Magnetic Nanoparticles as a Highly Selective Biosorbent for Recovery of Rare Earth Elements

“…91.9 and 87.0% of the MNP-LanM dispersed in geothermal brine and leachate of CFA could be recovered within 5 min, respectively (Figure 6B), which offers a facile and cost-effective approach to reuse the biosorbent. In comparison, previously reported LanM-based biosorbents such as elastinlike polypeptide 28 and yeast cells 29 mainly relied on expensive centrifugation for separation. To test the reusability of the MNP-LanM, we performed multiple cycles of Tb adsorption and desorption in geothermal brine.…”

Self-Sufficient Reusable Biocatalytic System Outfitted with Multiple Oxidoreductases and Flexible Polypeptide-Based Cofactor Swing Arms

“…After 48 h, the cells were harvested by centrifugation at 6000 g for 10 min before storage at −80 °C. The ELP purification procedure via inverse transition cycling (ITC) has been previously reported . Briefly, the cell pellet was resuspended in phosphate buffer saline (PBS) (pH 7.4), 1 mg/mL lysozyme, deoxyribonuclease I (DNase I), and ribonuclease A (RNase A) and lysed by sonication (amplitude: 28%, on/off: 2 sec/4 sec).…”

“…The ELP purification procedure via inverse transition cycling (ITC) has been previously reported. 43 Briefly, the cell pellet was resuspended in phosphate buffer saline (PBS) (pH 7.4), 1 mg/mL lysozyme, deoxyribonuclease I (DNase I), and ribonuclease A (RNase A) and lysed by sonication (amplitude: 28%, on/off: 2 sec/4 sec). The insoluble cell debris was removed by centrifugation at 13,000g for 30 min, and S-ELP was purified by repeating hot and cold spin cycles of ITC.…”