Towards precision bio(hydro)metallurgy: tailored biological systems for rare earth element recovery from dilute and secondary streams

Rare earth elements (REEs) are indispensable to technologies underpinning the energy transition, advanced manufacturing and digital infrastructure. However, their extraction and separation remain resource-intensive and are increasingly challenged by declining ore grades and the growing importance of dilute, chemically complex secondary resources. Biological processes offer a complementary strategy by exploiting molecular recognition mechanisms beyond conventional physicochemical separations. Biological macromolecules, cellular structures and metabolic processes create affinity-driven, three-dimensional binding environments that enable selective enrichment and recovery of REE groups, while high-resolution separation of individual lanthanides is currently achievable primarily through advanced affinity-based systems. This perspective examines emerging approaches to biological REE recovery, including bioleaching, biosorption, bioaccumulation, extracellular polymeric substances, lanthanide-binding proteins, and engineered biomaterials. We argue that their greatest near-term value lies in hybrid deployment, where biological systems act as selective solubilization, enrichment or polishing modules integrated with established hydrometallurgical operations. Particular emphasis is placed on scalable engineering solutions, including immobilized biosorbents and modular recovery systems compatible with existing metallurgical infrastructure. Realizing this potential requires a shift from proof-of-concept studies in simplified laboratory solutions toward validation in industrial leachates, rigorous assessment under realistic competitor-ion conditions, regeneration and reuse of biological materials, and integrated techno-economic and life-cycle analyses. Framing biology as a programmable platform for selective metal recognition and enrichment establishes a pathway toward hybrid recovery technologies supporting a more circular and sustainable critical mineral supply.