The bacterium Shewanella oneidensis strain MR-1. Credit: PLoS
Key points:
- Rare earth metals are an important power source, but retrieving them from raw ores is a costly and environmentally damaging process.
- Researchers have modified the genome of the S. oneidensis microbe to prefer rare earth metals in an effort to develop a new purification system.
- The microbe-driven process would be a scalable and sustainable alternative to current processing methods.
Rare earth metals power electric cars, wind turbines, and smartphones, but retrieving these materials from raw ore relies on harsh acids and organic solvents. These methods are costly and damage the environment. However, new technology, detailed in Scientific Reports, utilizes microbes to process rare earth elements in a clean and scalable manner.
“Currently all the purification of rare earth elements is done abroad, due to stringent environmental regulations and high infrastructure costs of building a separations plant,” said lead author Sean Medin of Cornell University. “Our process would make environmentally harmful solvents unnecessary.”
To develop their green alternative for purification, scientists initially characterized the genome of a metal-loving bacteria––S. oneidensis. Typically, S. oneidensis adsorbs lanthanides, including europium. After characterizing its genome, researchers could tweak its preference for processing other rare earth elements.
These findings enable the replacement of harsh chemical processing with a safe, scalable, and sustainable method known as biosorption. In fact, the research team expects to implement a pilot-scale purification system by 2028.
“Our process potentially would be significantly less land- and capital-intensive to build,” said Medin. “Our separations could be done with repeated enrichment through columns full of immobilized bacteria instead of mixer-settler plants that are miles long.”