A Chilean scientist is testing a ‘metal-eating’ bacteria which she believes could clean up the country’s high-polluting mining industry.
Biotechnologist Nadac Reales in her laboratory in Antofagasta, has shown how extremophiles – organisms that live in extreme environments – can eat a nail in just three days.
The basis of her research stems from her university days where she conducted tests at a mining plant using microorganisms to improve the extraction of copper.
In an interview with Agence France-Presse (AFP), Reales said that metals can be recycled in smelting plants but others, such as HGV truck hoppers that can hold 50 tons of rock, cannot and are often discarded in Chile’s Atacama desert, home to the majority of the country’s mining industry.
This isn’t surprising as Chile is the world’s largest producer of copper. The metal accounts for up to 15% of the country’s GDP, resulting in a lot of mining waste that pollutes the environment.
Reales believes the answer to this problem lies in the iron-oxidizing bacteria called Leptospirillum. She has even started a company – Rudanac Biotec – to explore the same.
As part of her study, Reales extracted the bacteria from the Tatio geysers located 4,200 meters above sea level.
Leptospirillum live in an acidic environment that is practically unaffected by relatively high concentrations of most metals.
At first, the bacteria took two months to disintegrate a nail. But when starved, they had to adapt and find a way of feeding themselves.
After two years of trials, the result was a marked increase in the speed at which the bacteria “ate,” devouring a nail in just three days, says Reales.
What’s more, the company’s chemical and microbiological tests have proven that the bacteria are not harmful to humans or the environment.
There’s another plus to the whole process: When the disintegration process is complete, what remains is a reddish liquid residue, a solution known as a lixiviant that itself possesses a surprising quality.
“After biodisintegration the product generated (the liquid) can improve the recovery of copper in a process called hydrometallurgy,” says Reales.
Essentially, the liquid residue can be used to extract copper from rock in a more sustainable manner than the current use of chemicals in leaching.
Reales says it means green mining is ‘totally feasible.’
Image and content: Paula Bustamante-AFP via PhysOrg