Biological Extraction of Rare Earth Elements Inspired by Processes in the Earth (BE RIPE)
Abstract
Current mining technologies for rare earth elements (REEs) use industrial processes that are unsustainable and economically uncompetitive, putting our economy and national security at risk. While initiating new mining efforts for REEs domestically is prohibitively expensive, there are REE-rich waste streams that are less costly to develop. To capitalize on REE metal-rich waste streams such asacid mine drainage, we need to explore new basic science approaches to concentrate and purify REEs from other metals. While many biologically-based REE purification schemes involve single steps, geologic studies of natural REE-rich deposits inspire us to considerhow multistep biogeochemical processes can be used to selectively concentrate REEs. The overall objective of this research is to develop biomaterials for a REE capture and enrichment process that mimics biogeochemical processes. These materials will be synthesized by microorganisms and are designed to have both natural and enhanced affinities for REEs. We will develop these materials using separate organisms with the aim of then combining them together into an integrated process. This work will use (1) natural iron oxyhydroxide biomineralization by an autotrophic iron-oxidizer to concentrate REEs, (2) strategies to differentially release REEs from biomineralized iron and initiate separation, and (3) an engineered extracellular matrix produced by freshwater oliogtrophic bacteria to achieve highly selective REE capture and concentration. We will isolate metal-tolerant, iron oxyhydroxide stalk-forming Gallionellaceae from acid mine drainage systems and optimize REE incorporation into the iron biominerals. Our next step will be to formulate processes for initial separation of REEs from Fe and other metals, for which we will explore a combination of desorption, mineral transformation and active biological uptake processes. The final step in the scheme will involve development of REE-specific purification material by programming Caulobacter crescentus to produce an extracellular protein matrix with high affinity, high selectivity REE binding sites. Our approach minimizes nutrient inputs by using an autotroph and oligotroph, while also taking advantage of a newlydeveloped engineered living material that can be programmed to display lanthanide binding proteins on a self-made, regenerating matrix.This research project will contribute to the Biomaterials and Bionanotechnology Program by: i) developing strategies to synthesize and pattern materials using microorganisms and ii) developing fabrication processes that create hierarchically-structured materials with predicted function. We envision that the proof-of-concept experiments also will lead to the development of new technologies and processes for recovery of REEs needed for Naval operations.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 06, 2021
- Source ID
- N000142112361
Entities
People
- Clara Chan
Organizations
- Office of Naval Research
- United States Navy
- University of Delaware