One of the greatest challenges in making otherwise clean technologies truly green and sustainable is the difficulty associated with recycling rare earth elements, or REEs. REEs are chemically similar elements that have been used in the manufacture of various advanced metals for high-technology products, like magnets and lasers.
As an example, neodymium is used in a lot of green technologies, like electric cars and wind turbines.
REEs are essential to a variety of products, but extracting them is an environmentally disastrous process. One ton of REEs produces 75 cubic meters of acidic waste water that can be incredibly damaging the soil. Another problem associated with REEs is that they’re often located in nations that are geopolitically inaccessible. This is why recycling REEs is so important. But about ability to do so has been limited due to cost and the fact that REE recycling is also kind of bad for the environment.
Researchers at the University of Tokyo have been investigating whether or not bacteria could be used to recover spent REEs. They found that the phosphate site on bacterial cell walls can serve as a binding site of REEs, which is what lead them to the possibility that DNA could be used to extract REEs in a solution.
But they faced one glaring problem: DNA is soluble in water. So they needed a source of DNA that wouldn’t break down water.
Enter: salmon sperm.
Salmon sperm, or milt, is inexpensive, insoluble, and there are literally thousands of tons of the stuff discarded each year by the fishing industry. Scientists have tested it out and found that metal bonds strongly with salmon sperm. REEs can be easily extracted using an centrifugal acid bath. It’s not perfect, but it’s promising.
Thanks, salmon friends!