Metal-Eating Bacteria That Chomps On Nails Could Make Mining More Environmentally Friendly

Leptospirillum is extremely metal if you are what you eat. Leptospiriium is a genus of microbes that feed on metals, specifically iron when none of their usual diets are available. Nadac Reales, a Chilean scientist, is aiming to use this ability to clean up previous mining sites and has tweaked her microbial agents to the point where they can digest a nail in three days. Other scientists are mining with biological agents as well, but they are after metals that are more exotic. Chile is the world’s largest copper producer. Because many low-carbon technologies, such as electric cars, require more copper than the technologies they replace, demand expected to rise. Reales was working on using microbes to improve copper extraction when she discovered they may be more useful by cleaning up the pollution left behind by mining activities, according to an AFP profile.

“I noticed there were a variety of demands in the mining industry,” Reales told AFP. “For example, what occurred with the metallic trash?” Because gaining energy through oxidizing metals is more difficult than getting it from sunlight or consuming something that does, creatures that make a living out of it tend to dwell in extreme environments, earning the moniker extremophiles.

Reales began looking for creatures that would fit her demands in locations that were unfriendly to most life. She discovered Leptospirillum that grows in acidic situations and can endure high metal concentrations at the Tatio geysers in the Atacama Desert, the world’s highest-altitude geyser field in possibly the world’s harshest desert. “At first, the bacteria took two months to destroy a nail,” Reales told AFP of their ability to break down metal objects. However, she discovered that when the Leptospirillum was deprived of other food sources, it became hungry enough to concentrate on the task.

Reales was able to reduce the nail-consuming time to three days after two years of selecting the most suitable strains and changing the environment in which she kept them. Reales founded Rudanac Biotec to take advantage of this capacity, and he is looking for funding to expand the operations and determine how long it takes to move 50 tons of rock.

Leptospirillum does not represent a hazard to persons or healthy settings, according to Reales, and their capabilities extend beyond repair. After all of the iron has consumed, the reddish liquid left behind can be employed to boost copper recovery by replacing harmful leaching chemicals.

Reales are one of several scientists trying to figure out how to extract metals via biological processes. Dr. Josepch Cotruvo of Penn State University is part of a team that has shown that bacteria are not always required to complete the job. Cotruvo and co-authors published a paper in ACS Central Science demonstrating the utilization of Ianmodulin, a bacterial protein, for metal extraction in mines and electronics recycling. Lanmodulin binds to rare Earth metals, which are commonly found in cell phones, electric vehicles, and wind turbines. Although rare Earths are not as rare as their name implies, they are difficult to extract in environmentally safe ways, and refineries that could break China’s near-monopoly on their production have been opposed due to processing damage more than the mining themselves. Lanmodulin has the potential to solve this problem.