Chilean scientist plans to clean up mining with 'metal eating' bacteria

Nadac Reales, a Chilean biotechnologist, shows a screw and nail inside a jar containing metal-eater bacteria. This is her laboratory at Antofagasta's mining site.
Microorganisms that can survive in extreme conditions and starvation have been able to "eat" nails in three days.

Chilean scientist tests "metal-eating bacteria" in hopes of helping to clean up Chile's highly polluting mining industry.

In her laboratory in Antofagasta, an industrial town 1,100-kilometers north of Santiago, 33-year-old biotechnologist Nadac Reales has been carrying out tests with extremophilesorganisms that live in extreme environments.

Reales had an idea for the project while she was still in university. She was working at a mine plant that used microorganisms to increase copper extraction.

She told AFP that she realized that there were many needs in the mining industry. For example, what happens to the metallic waste.

While some metals can still be recycled in smelting facilities, others such as HGV truck trucks hoppers that can carry 50 tons of rock can't and are often discarded in Chile’s Atacama desert. This desert is home to most of Chile's mining industry.

Chile is the largest copper producer in the world, accounting for around 15% of Chile's GDP. This results in a lot mining waste that pollutes our environment.

Reales, now the owner of Rudanac Biotec and a researcher herself, focused on Leptospirillum, an iron-oxidizing bacteria.

She took the bacteria from Tatio geysers at 4,200m above sea level, about 350 km from Antofagasta.

She said that the bacteria lives in an acidic environment, which is virtually unaffected with relatively high levels of most metals.

"It took the bacteria two months to break down a nail.

They had to find a way to survive when they were starved.

Two years of testing led to a significant increase in the rate at which bacteria "ate" nails. It took just three days for the nail to be eaten.

Chilean scientist Nadac Robertles hopes that her "metal eating" bacteria will make green mining "totally possible."

Surprising benefit

Reales claims that "chemical and microbiological testing" have proven the bacteria to be safe for humans and the environment.

Drina Vejar, a microbiologist and part of a four-person team with Reales, said that "we've always seen lots of potential in the project that has already passed a crucial test in the laboratory."

"It is really important at this point when we must plan for a more durable development, especially in cities with so many polluting industry."

Although mining companies are interested in the research, Rudanac Biotec has previously received funding from the state for start-ups. The company now needs to raise capital to continue its trials.

Reales claims she needs money to test if her method can "eat a medium-sized beam or ahopper."

After the process of disintegration is completed, there is still a reddish liquid remnant, which is known as a "lixiviant" and has a surprising quality.

Reales stated that "after biodisintegration, the product (the liquid) can enhance the recovery of copper through a process called Hydrometallurgy."

The liquid residue can be used to extract the copper from the rock in a more sustainable way than current chemical leaching.

Reales said it meant that green mining was "totally possible."

This is of great importance to mining companies, as they could use it for large-scale copper extraction or other minerals. They also have to reduce their pollution, which is something they are required by law.

Reales submitted an international patent request for her technology. But, she also hopes that it will reduce the amount of metal waste in the country's mining areas.

Continue reading Non-toxic technology extracts even more gold from ore

2021 AFP