Publication Date
1-9-2024
Document Type
Article
Publication Title
Environmental Science and Technology
Volume
58
Issue
1
DOI
10.1021/acs.est.3c06775
First Page
570
Last Page
579
Abstract
Chemical methods for the extraction and refinement of technologically critical rare earth elements (REEs) are energy-intensive, hazardous, and environmentally destructive. Current biobased extraction systems rely on extremophilic organisms and generate many of the same detrimental effects as chemical methodologies. The mesophilic methylotrophic bacterium Methylobacterium extorquens AM1 was previously shown to grow using electronic waste by naturally acquiring REEs to power methanol metabolism. Here we show that growth using electronic waste as a sole REE source is scalable up to 10 L with consistent metal yields without the use of harsh acids or high temperatures. The addition of organic acids increases REE leaching in a nonspecific manner. REE-specific bioleaching can be engineered through the overproduction of REE-binding ligands (called lanthanophores) and pyrroloquinoline quinone. REE bioaccumulation increases with the leachate concentration and is highly specific. REEs are stored intracellularly in polyphosphate granules, and genetic engineering to eliminate exopolyphosphatase activity increases metal accumulation, confirming the link between phosphate metabolism and biological REE use. Finally, we report the innate ability of M. extorquens to grow using other complex REE sources, including pulverized smartphones, demonstrating the flexibility and potential for use as a recovery platform for these critical metals.
Funding Number
DE-AR0001337
Funding Sponsor
U.S. Department of Energy
Keywords
acid-free leaching, bioaccumulation, bioconcentration, bioleaching, electronic waste, lanthanide, metal-binding protein, neodymium
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Department
Biomedical Engineering; Biological Sciences
Recommended Citation
Nathan M. Good, Christina S. Kang-Yun, Morgan Z. Su, Alexa M. Zytnick, Colin C. Barber, Huong N. Vu, Joseph M. Grace, Hoang H. Nguyen, Wenjun Zhang, Elizabeth Skovran, Maohong Fan, Dan M. Park, and Norma Cecilia Martinez-Gomez. "Scalable and Consolidated Microbial Platform for Rare Earth Element Leaching and Recovery from Waste Sources" Environmental Science and Technology (2024): 570-579. https://doi.org/10.1021/acs.est.3c06775
