Bacterium Gluconobacter oxydans could be key to sustainably extracting earth elements

In a study published in Nature Communications scientists have described a proof of principle wherein they have stated that an engineered bacterium Gluconobacter oxydans could be key to sustainably extracting earth elements.

Rare earth elements have become very critical for our technological lives and while they make our lives simpler, there is a heavy toll that we have to pay in terms of environmental costs. The new study could be one of the first steps towards meeting skyrocketing rare earth element demand in a way that matches the cost and efficiency of traditional thermochemical extraction and refinement methods and is clean enough to meet U.S. environmental standards.

The elements – of which there are 15 in the periodic table ­– are necessary for everything from computers, cell phones, screens, microphones, wind turbines, electric vehicles and conductors to radars, sonars, LED lights and rechargeable batteries.

While the U.S. once refined its own rare earth elements, that production stopped more than five decades ago. Now, refinement of these elements takes place almost entirely in other countries, particularly China.

To meet U.S. annual needs for rare earth elements, roughly 71.5 million tonnes (~78.8 million tons) of raw ore would be required to extract 10,000 kilograms (~22,000 pounds) of elements.

Current methods rely on dissolving rock with hot sulphuric acid, followed by using organic solvents to separate very similar individual elements from each other in a solution.

G. oxydans is known for making an acid called biolixiviant that dissolves rock; the bacteria uses the acid to pull phosphates from rare earth elements. The researchers have begun to manipulate G. oxydans’ genes so it extracts the elements more efficiently.

To do so, the researchers used a technology that Barstow helped develop, called Knockout Sudoku, that allowed them to disable the 2,733 genes in G. oxydans’ genome one by one. The team curated mutants, each with a specific gene knocked out, so they could identify which genes play roles in getting elements out of rock.

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