Fish Sperm Might Be the Secret to Recycling Rare Earth Elements

Japanese scientists have uncovered an unlikely source to aid in the extraction and recycling of rare earth metals

Salmon NF003289.jpg
Natalie Fobes/CORBIS

File this under: Awesome things you didn’t know fish semen was good for.

The DNA within salmon milt (or semen) has been found capable of aiding in the extraction and recycling of the rare earth metals commonly used in technologies from smart phones to wind turbines.

A team of scientists in Japan made this discovery while seeking out better ways to extract rare earth elements like neodymium from the crude ore in which they are found. Current methods use large amounts of environmentally damaging chemicals, including mercury and arsenic, and are severely compromising water sources in mining regions like parts of China.

As Newsweek reports:

The scientists, led by Yoshio Takahashi of Hiroshima University, found that several rare earth elements bound strongly to phosphate-containing molecules on the surface of bacterial cells, according to Chemistry World, a publication of the Royal Society of Chemistry. So they turned to salmon sperm, since it is largely made up of DNA, which contains a lot of phosphate. (And it’s also insoluble in water, unlike pure DNA, making it easier to work with.)

When applied to neodymium, the team found that the salmon milt DNA made a strong bond with the metal, allowing its subsequent extraction following an acid bath and a spin through a centrifuge.

Salmon semen has the benefit of being both cheap and green. Even better, experts say the discovery could be applied to recycling rare earth metals used in smart phones, computers and electronic circuits—metals that otherwise would end up in a landfill.

This isn’t the only research performed on the wondrous powers of fish semen. Previous studies have found that the same DNA that binds to metals like neodymium also lends itself to fireproof coating. As for fish semen in its natural form: it is considered a delicacy in Japan.