CAREER: Elucidating the Chemistry of Biological Lanthanide Chelators for Rare Earth Element Separation

About This Grant

The Chemistry of Life Processes Program in the Chemistry Division is funding Dr. Allegra Aron from the University of Denver to identify and characterize small molecules produced by bacteria found in soil and on plants that bind to lanthanide (Ln) metals. Ln metals, such as lanthanum and neodymium, are rare earth elements (REEs) that are raw materials for the production of critical technological and national security components (such as computers, cellphones and radar/sonar systems). The objective of this project is to define the structural and Ln binding properties of these bacterial molecules, with the long-term goal of developing biology-based methods for the separation, isolation and recovery of REEs. The educational plan will educate the next generation of scientists by providing merit-based paid laboratory internships to Denver Public high school students in participating chemistry labs and across the College of Natural Sciences. In addition, graduate students and researchers will be prepared for interdisciplinary research through weekly virtual office hours and in-person summer school workshops hosted by a collaborative virtual metabolomics laboratory. The overall objective of this proposal is to understand the origins of metal- and uptake-selectivity through the isolation and characterization of Ln-chelators with varied structures isolated from one-carbon metabolizing methylotrophic bacteria. Results from preliminary genome mining suggest significant structural variation exists across biological Ln-chelators, such that specificity may exist in both metal-binding and in molecular recognition. Liquid chromatography-based mass spectrometry along with computational workflows, statistical pipelines, and metal-infusion experiments will be used to discover novel chelators from five organisms in the Methylobacteria and Methylorubrum families of bacteria. The chemical structures and selectivity in binding between Ln and iron (a more ubiquitous competitor metal) of putative chelators will be characterized through various spectroscopy methods ranging from UV-visible to magnetic resonance spectroscopies. Finally, the biological roles of these chelators in the accumulation of Ln versus iron will be determined using a host of molecular biology techniques, along with assessment of metal uptake. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.