Get Regular Updates!



S. Chang, S. H. Park, D. H. Kang/International Journal of Food Microbiology

Bacteria breaking down mountains

Bacteria breaking down mountains

How do you break down kilometres of rock to get the metals within? You go small. Bacteria-level small.

Bacteria breaking down mountains

If you’ve got a big rock with a little bit of metal in it, how do you get it out?

Most of the time, you would smash it and dunk it in powerful acid until everything dissolves, then sieve out the metal.

But what if that big rock is thousands of kilometres across? That’s a lot of acid to buy. Not to mention how detrimental it could be for the environment.

What if you could get someone who could make acid where it was needed, without compromising the environment? Like a worker … who gets paid in water.

The smallest employee

Bioleaching uses bacteria that make their own organic acids to break down minerals. As the bacteria feed, they expose rare-earth metals, which run off in the water fed through the rock.

Because the valuable metals are in the run-off, the bioleaching system is contained, meaning less pollution than traditional methods.

Professor Elizabeth Watkin is a researcher in molecular microbial ecology at Curtin University. She studies how tiny things like bacteria, viruses and fungi interact with the environment.

“We were looking at a phosphate-based rare-earth ore, monazite. It’s critical to today’s society because it contains cerium and lanthanum,” says Elizabeth.

Phosphate is an oxygen-laden mineral found in many foods.

Lanthanum alloys and cerium are used in lights, batteries and medicine. These rare-earth metals are trapped inside rocks, surrounded by phosphate molecules, which the bacteria eat.

“These organisms are already used widely in agriculture to make phosphate available in the soil to encourage plant growth. We apply that agricultural knowledge to these minerals,” says Elizabeth.

View Larger
Image|Collie River Valley Marketing Group
One bioleaching bacteria species was found in an old coal mine in Collie, Western Australia

“We’re actually one of the first groups to look at rare-earth bioleaching. It’s us and a group at UC Berkley in the United States. We’ve proven it works, and now we’re reaching out to engineers to try and incorporate it into their mining operations.”

Bacteria on acid

While bioleaching for rare-earth metals is new, the method is already being used to mine copper in Western Australia and around the world.

These bioleaching piles are giant living reactors that break down rocks for energy. They can be thousands of kilometres across.

View Larger
The largest bioreactor in the world in Chile – it’s 10,000 square miles of bacteria eating rock

Water is drip filtered through the rock, allowing the bacteria to grow and letting the metals collect in the run-off.

One local species used for bioleaching was actually found in an old open-cut coal mine in Collie, Western Australia.

While the acidic, toxic environment doesn’t seem like a cosy home, it was an all-you-can-eat-buffet for Alicyclobacillus acidocaldarius.

Wrong kind of acid …

These bacteria have evolved to use those elements as part of their metabolism – much like the mineral-munching microbes found around volcanic vents under the sea.

“In this space, we work with iron and sulphur-oxidising bacteria,” says Elizabeth.

“When iron and sulphur are oxidised, they release electrons which the bacteria use for ATP [energy] production.”

In the wild, these bacteria are harmful, releasing their acid into nearby water systems. But when controlled, they may actually prove more environmentally friendly than the artificial acids whose jobs they’re taking.

Particle Puns


Creative Commons Logo

Republishing our content

We want our stories to be shared and seen by as many people as possible.

Therefore, unless it says otherwise, copyright on the stories on Particle belongs to Scitech and they are published under a Creative Commons Attribution-NoDerivatives 4.0 International License.

This allows you to republish our articles online or in print for free. You just need to credit us and link to us, and you can’t edit our material or sell it separately.

Using the ‘republish’ button on our website is the easiest way to meet our guidelines.


You cannot edit the article.

When republishing, you have to credit our authors, ideally in the byline. You have to credit Particle with a link back to the original publication on Particle.

If you’re republishing online, you must use our pageview counter, link to us and include links from our story. Our page view counter is a small pixel-ping (invisible to the eye) that allows us to know when our content is republished. It’s a condition of our guidelines that you include our counter. If you use the ‘republish’ then you’ll capture our page counter.

If you’re republishing in print, please email us to let us so we know about it (we get very proud to see our work republished) and you must include the Particle logo next to the credits. Download logo here.

If you wish to republish all our stories, please contact us directly to discuss this opportunity.


Most of the images used on Particle are copyright of the photographer who made them.

It is your responsibility to confirm that you’re licensed to republish images in our articles.


All Particle videos can be accessed through YouTube under the Standard YouTube Licence.

The Standard YouTube licence

  1. This licence is ‘All Rights Reserved’, granting provisions for YouTube to display the content, and YouTube’s visitors to stream the content. This means that the content may be streamed from YouTube but specifically forbids downloading, adaptation, and redistribution, except where otherwise licensed. When uploading your content to YouTube it will automatically use the Standard YouTube licence. You can check this by clicking on Advanced Settings and looking at the dropdown box ‘License and rights ownership’.
  2. When a user is uploading a video he has license options that he can choose from. The first option is “standard YouTube License” which means that you grant the broadcasting rights to YouTube. This essentially means that your video can only be accessed from YouTube for watching purpose and cannot be reproduced or distributed in any other form without your consent.


For more information about using our content, email us:

Copy this HTML into your CMS
Press Ctrl+C to copy

We've got chemistry. Want something physical?