Saving the Environment with Metal Eating Bacteria

A Chilean scientist believes manipulating extremophile bacteria to eat metal can save the environment from mining waste.

Sitting in her laboratory 1,100 kilometers north of Santiago, Nadac Reales watched bacteria devour a nail in only 3 days. It was an idea she’d had since university. Working closely with her country’s many mining plants to increase the efficiency of copper extraction, she focused on using microorganisms to help separate copper from the surrounding ore, a process known as biomining. Today, she has her own company, an international patent, and an idea she believes will save the environment from the destructive nature of the mining industry.

The Electron Thief

Reales traveled to the acidic Tatio geyers, over 4000 meters in the Chilean Andes to collect bacteria called Leptospirillum. This was chosen for two reasons. First, it’s an extremophile, meaning it can survive in extremely harsh conditions, such as in the presence of metals that are often toxic for other bacteria. Second, it can oxidize metals. It steals electrons, turns them into an energy source, and slowly degrades the metals over time. A famous example of this process is the bacteria eating the Titanic at the bottom of the Atlantic.

Reales’ idea is to use Leptospirillum to break down abandoned mining equipment and other metallic waste left behind by mining companies. However, normal Leptospirillum needs a lot time to do this, making it infeasible. In Reales’ first test years ago, the bacteria needed two months to eat the nail. But she found a way to starve the bacteria, forcing it to adapt, and when given the nail after being starved, they ate it within 3 days. The byproduct of this process is red residue called lixiviant, which offers a handful of other benefits. In particular, lixiviant can be used to extract copper in a way that is far greener than other methods.

Therefore, Reales is confident that her starved Leptospirillum will be able to eat the massive amounts of mining equipment that pollute not just her home country of Chile but numerous others as well, leaving behind a residue that can further reduce mining’s negative environmental impact. She described it as a “unique patented process worldwide that allows biodesintegration of metal scrap, using microorganisms that feed on metal without generating polluting waste, it is friendly to the environment, profitable, scalable, easy to implement.” 

Desolation Desert

In 2018, American photographer David Maisel was granted rare access to the skies above Chile’s Atacama Desert, allowing him to document the widespread mining and environmental degradation. For many, this was their first look at the heart of the country’s mining operations, a lot of which produces copper, generating 15% of the country’s GDP. In recent decades, though, mining resources have shifted towards extracting lithium, largely due to its use in electronics and batteries, especially those needed for electric cars. For example, Maisel notes that “one version of the Tesla automobile runs on a battery with 140 pounds of lithium compounds, the equivalent of what is found in about ten thousand cell phones.”

It was working here and other similar places that inspired Reales. This is because the Atacama Desert is a dumping ground for old mining equipment, which is left to degrade naturally, leeching dangerous heavy metals into the soil and groundwater, among many other problems. The local population is caught in a perpetual fight with mining corporations over their water, which is gradually growing more and more undrinkable.

Globally, scrap metal is a major issue, especially in developing countries, as they often lack the environmental regulation and technical capabilities to prevent pollution. Reales claims that much of this pollution is “generated by vehicle cemeteries, mining industries, industrial machinery, construction structures, ships, containers and railway industries, among others.”

If Reales and her company Rudanac Biotec gets the funding needed to move forward, she’ll be able to help clean up a lot of this waste, while making mining cleaner.