Microbe-Mineral Interactions for Rare Earth Recovery
EMSL Project ID
50271
Abstract
Lanthanides are composed of 15 metallic chemical elements (La-Lu). Combined with Sc and Y, they are often collectively known as the rare earth elements (REEs). Although lanthanides are ubiquitous in the environment, they have long been regarded as non-biological metals. However, the recent discovery of a lanthanide-dependent methanol dehydrogenase in several bacteria suggests that lanthanides may serve an underappreciated role in biology. Additionally, the preferential cell surface adsorption of REEs over non-REEs by many microorganisms highlights a likely role for microbes in affecting REE transport and mobility in the environment. Since anthropogenic contamination of REEs is expected to increase with increasing application and usage of REEs in high-tech industry and consumer products, the environmental relevance of microbe-REE interactions will be increasingly important. Funded by the DOE/EERE Critical Materials Institute (CMI), the proposed study focuses on fundamental studies of native and engineered microbe-mineral interactions with a central goal of enabling REE recovery from low-grade feedstocks. REEs are in high demand in renewable energy, consumer products, and many defense and national security applications, but current uncertainty regarding REE availability via global markets hinders the growth of domestic industries. The abundance of several non-traditional REE resources in the U.S., such as mine tailings, geothermal brines and coal byproducts, offers an attractive alternative for obtaining REEs. However, the low REE content typical in these feedstocks prohibits conventional REE extraction, and no technology currently exists that can cost-effectively extract REEs from these feedstocks.
To address the need for cost-effective recovery of REEs from low-grade feedstock, we have developed a novel biotechnology that couples the native bacterial surface properties with enhanced bioengineered features to sequester REEs. Through EMSL support, we will characterize biogenic mineral phase and structure and elucidate the functions of cell/biofilm surface structures that facilitate rare earth biosorption/biomineralization from low-grade feedstocks. Our specific aims include 1) characterization of microbe-mineral interactions and the function of biological factors including lanthanide binding tags, lanthanide mineralization tags, and a native phosphatase enzyme in affecting REE biosorption and biomineralization on the cell surface; 2) building and characterizing designer biofilms to enable cell immobilization for flow-through REE recovery operations; and 3) examining the potential application of biomineralization of rare earth hydroxides and phosphates for REE recovery.
The imaging instrumentation at EMSL provides various capabilities and technical expertise needed for the project. The correlative, multimodal, and integrative bioimaging capabilities, in particular, are critical for the proposed biosystems design research. The availability of HIM provides nanoscale topographical and surface imagining ideal for studying microbe-mineral (nanoparticle) interactions of intact specimens. EMSL has one of only a few HIM's available for user access. Additionally, S/TEM provides nanoscale imaging of curli fibrils and cell surface morphologies, which will yield insights into the structural consequences of cell-surface LBT/LMT display and biomineralization.
The proposed imagining analyses will advance our knowledge of how minerals interact with native/ engineered microbes and biofilms at submicron resolution. Successful execution will improve our understanding of the role of cell surface anchor proteins and appendages in biosorption and biomineralization. Insight gained will provide feedback for the development of the designed biological systems for mineral recovery. In addition to having a direct application to mineral recovery, the proposed molecular-scale functional biology will also deepen our understanding of the role of microbial processes in rare earth biogeochemistry in natural and perturbed ecosystems.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2018-10-01
End Date
2021-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)
Related Publications
Brewer B., A. Dohnalkova, V. Shutthanandan, L. Kovarik, E. Chang, A.M. Sawvel, and H.E. Mason, et al. 2019. "Microbe Encapsulation for Selective Rare-Earth Recovery from Electronic Waste Leachates." Environmental Science & Technology 53, no. 23:13888-13897. PNNL-SA-156048. doi:10.1021/acs.est.9b04608