US researchers present a more environmentally friendly process for separating the critical raw materials.
The demand for raw materials for the energy transition is growing, but at the same time, there is a risk of supply bottlenecks due to their limited availability. As new mining projects have very long lead times, alternative extraction methods are becoming increasingly important. Researchers at Cornell University in the US state of New York have now presented a method in which Vibrio natriegens, a bacterium weighing just one trillionth of a gram, plays the main role. It is capable of dissolving rare earths from e-waste, for example, selectively binding them to itself and thus separating them from one another. According to the study published in the journal Synthetic Biology, this so-called biosorption has been improved through genetic modification. Compared to the wild type, the newly developed bacterial strain has a 50 per cent higher selectivity with regard to a total of 17 rare earth elements. It can also biosorb 210 percent more of the heavy rare earth metal dysprosium, which is considered particularly critical.
Compared to conventional methods of separating the raw materials using solvents, this is a more environmentally friendly approach, explains lead author Buz Barstow. The expertise in separating rare earths has largely been lost in the USA; the minerals extracted here are currently sent to China for processing, which has a quasi-monopoly on this technology. In the future, bacteria such as Vibrio natriegens could be used in the USA’s rare earth mine, Mountain Pass, and strengthen the domestic supply chain, says Barstow.
More on bacteria as miners: A research team led by Buz Barstow has already trialled genetic engineering methods on another bacterium, Shewanella oneidensis, in order to extract rare earths in an environmentally friendly way. Further projects on the extraction of raw materials using microorganisms are being researched at the University of Nottingham, the Technical University of Denmark and the San Diego State University, among others.
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