Metal-Eating bacteria that can eat a nail in three days found in the Andes

Starving microorganisms that were able to eat a nail in just three days could help clean up waste left over from mining. The metal-eating bacteria currently being tested in Chile could also provide a by-product that helps extract copper, making the mining of the metal more environmentally friendly.(Left) Stock image of a rusty nail. (Right) Stock illustration of bacteria under a microscope. A Chilean researcher hopes that a metal eating bacteria that ate a nail in three days in her lab could be used to clean up mining waste.A Chilean researcher hopes that a metal eating bacteria that ate a nail in three days in her lab could be used to clean up mining waste.

Chilean biotechnologist Nadac Reales has been working with extremophiles, organisms that are capable of living in conditions of extreme temperature, acidity, alkalinity, or chemical concentration, in her lab. “I realized there were various needs in the mining industry, for example, what happened with the metallic waste,” Reales told Agence France-Presse.

Mining is a huge industry in Chile, with around 10 to 15 percent of the South American country’s gross domestic product coming from copper production. This leads to a great deal of solid mining waste. Smaller metallic waste can be recycled in Chile’s smelting plants, but larger waste pieces, such as huge HGV truck hoppers capable of holding 50 tons of rubble, cannot.

This leads to large solid metal waste pieces being discarded throughout the Atacama Desert in Chile’s northern region. Reale recovered the Leptospirillum bacteria from Chile’s Tatio geysers located in the Andes mountains, at around 2.5 miles above sea level, and around 200 miles from her lab in Antofagasta.

Initially, the bacteria, which live in highly acidic conditions, took two months to eat through a nail. As the Leptospirillum began to starve though, each subsequent generation evolved to better feed themselves.

As a result, after two years of experimentation, the speed at which the bacteria could consume a nail had greatly increased. It was eventually able to consume the object completely in just three days. Reale has discovered that not only does the Leptospirillum have remarkable metal disintegrating abilities, it causes no harm to the environment or to humans.

Additionally the by-product the bacteria leave behind when they consume metal can be used to recover copper in a process called hydrometallurgy, which uses an aqueous solution to recover metal from its ore. This means that the bacteria could not just clean up mining waste, but could also provide a vital ingredient needed for the greener mining of copper.

“We’ve always seen a lot of potential in this project that has already passed an important test in the laboratory,” said a member of Reale’s four-person team, microbiologist Drina Vejar. “It’s really necessary at this time when we have to plan for a more sustainable development, especially in all these cities with so many polluting industries.”

The project is currently being developed by Reale’s company, Rudanac Biotec, but the researcher said that further trials will require more investment. With financial backing, the team hopes to discover if the Leptospirillum bacteria can “eat a medium-sized beam or a hopper.”


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