Oak bacteria could help treat rare earth elements TNA

A bacterial protein found in English oak buds could be used to more efficiently process the rare earth elements needed for different technologies.

Rare earth elements are used in products such as smartphone and television screens, electric vehicle motors and wind turbines. Natural deposits of these elements can be found and mined in several countries. But the industrial separation facilities needed to process them use an energy-intensive method that typically requires hundreds of steps and uses many toxic chemicals — something that could be simplified with natural shortcuts provided by a certain class of bacteria.

Joseph Cotruvo Jr. at Pennsylvania State University and his colleagues discovered that the bacterium Hansschlegelia quercus contains a protein that can help differentiate between lighter and heavier types of rare earth elements. They isolated the bacterium from English oak buds while examining hundreds of these bacterial proteins – building on their previous research showing how proteins found in the metrolyph class of bacteria can help separate rare earth elements from non-rare earth elements.

The team found that if the bacterial protein binds to a lighter rare-earth element, it is more likely to also bind to another unit of itself. If the protein binds to a heavier rare earth element, it is more likely to remain unique.

This discovery allowed researchers to show how the protein can help separate neodymium and dysprosium – light and the heavy rare earths respectively used in permanent magnets – in a single chemical step at room temperature without the use of toxic chemicals.

The approach could help deal with rare earth elements that have been mined from the ground or are recovered from recycled technology products.

The work is a “proof of concept” approach that still faces significant challenges in being able to process rare earth elements on a large industrial scale, says Jason Love at the University of Edinburgh in the UK. “A significant problem with the biochemical approach is to ‘manufacture’ enough proteins to be able to perform these large-scale separations.”