Developing biotechnologies for detection and recovery of Rare Earth Elements

This project will develop novel microbes with increased capability to dissolve and capture REE from solid sources such as crushed ore and e-waste. The project will also examine approaches to increase the selectivity and affinity of biomolecules for different REE. Additionally, the project will investigate different technologies/approaches that improve scalability of REE recovery processes (e.g. concentration and monitoring of REEs during processing). The ultimate goal of this effort is to develop methods that accelerate our ability to recover individual or discrete mixtures of REE from domestic primary and secondary sources. Objective 1: Increase the selectivity and affinity of biomolecules for different REE. We will create semi-synthetic platforms for specific lanthanide-binding, relying on modification of proteins and spores using designed chemical structures for chelation moieties. We anticipate that these will greatly improve the already robust concentration of lanthanides by spores and proteins, while providing methods for tuning protein/spore affinity and selectivity. The specificities of both the semi-synthetic and protein-alone chelators will be further modified using computational models to design peptides and proteins with a variety of affinities and specificities for REE.Objective 2: Technologies/approaches that improve scalability of REE recovery processes. We will alter the surfaces of fluorescent proteins in order to create protein biosensors that can bind lanthanides with high affinity and selectivity, and also allow FRET detection both in vitro and in vivo of lanthanides (samarium, europium, terbium, and dysprosium). Such biosensors will serve as extraordinary tools for monitoring the efficiencies of processing streams and of the efficacies of different technologies. We will also work with ERDC researchers to examine novel approaches to condense process streams to increase efficiency of downstream processing events. Objective 3: Develop novel microbes with increased capability to dissolve and capture REE from solid matrices. Microbes will be metabolically engineered to dissolve REE and capture REE from solid matrices. Organisms will be able to concentrate lanthanides, and then themselves be concentrated from waste streams. This will increase the amount of leached REE dissolved in leachate and increase the amount of REE isolated after purification Results from these objectives will be communicated to ERDC regularly in interim reports and transferred to the Public using conference presentations and the peer-reviewed literature. All methods and protocols will accompany the results and meet peer-review scrutiny for any interim reports.