Harnessing a Genetically Engineered Self-Assembling Protein Biosorbent for Efficient and Selective Rare Earth Element...

Area of Science:

• Biotechnology
• Materials Science
• Environmental Science

Background:

• Global demand for rare earth elements (REEs) is increasing for high-tech and clean energy applications.
• Conventional REE extraction methods are environmentally damaging and resource-intensive.
• Sustainable alternatives for REE recovery from low-grade secondary resources are needed.

Purpose of the Study:

• To develop a novel, efficient, and sustainable biosorbent for rare earth element recovery.
• To immobilize a functional protein (lanmodulin) onto a carrier for enhanced performance.
• To demonstrate the biosorbent's efficacy in recovering REEs from industrial waste.

Main Methods:

• Genetic fusion of *Hansschlegelia quercus* lanmodulin (*Hans*-LanM) to protein crystalline inclusions (PCIs) in *Escherichia coli* for one-pot immobilization.
• Characterization of the PCI-Hans-LanM biosorbent's adsorption and desorption kinetics and capacity.
• Testing the biosorbent's selectivity, reusability, stability, and performance in recovering REEs from coal fly ash leachate.

Main Results:

• The PCI-Hans-LanM biosorbent demonstrated rapid adsorption/desorption kinetics with capacities of 157.6–197.7 μmol-REE/g.
• High selectivity was observed, capturing REEs against over 2000-fold excess non-REEs.
• The biosorbent maintained performance over 10 reuse cycles and one-month storage, and achieved a 433-fold purity increase from coal fly ash leachate.

Conclusions:

• PCI-Hans-LanM is a highly effective and reusable biosorbent for sustainable rare earth element recovery.
• Bioengineering strategies can create advanced biosorbents for efficient REE extraction from waste streams.
• This approach contributes to a circular economy and diversifies the rare earth element supply chain.