Microbes can extract valuable elements from rocks in space

RRecent experiments aboard the International Space Station have shown thatme, microbes can harvest precious rareelements of earth rocks, even when exposed to microgravity conditions. This unexpected discovery shows how microbes could enhance our ability to live and work in space.

On Earth, some microscopic organisms have shown their value as efficient miners, extractingEarth elements (REE) of rocks. New experimental evidence published today in Nature Communications shows that when it comes to leaching REEs of rocks, at least one strain of bacteria is largely unaffected by microgravity andgravity conditions. This is potentially good news for future space explorers, as biomining microbes could provide a way to acquire rare earths in space, on the Moon, or on Mars.

REEs are vitally important for the manufacture of commercial electronic components (like those found in your smartphone) and the production of alloys. The problem with rare earths, apart from their names (eg, lanthanum, cerium, neodymium, yttrium, praseodymium, to name a few), are not so uncommon that they are notoriously difficult to squeeze and extract, making it a severe pain in the ass. In addition to the increase in extraction and refining costs, harvesting these elements is both ecologically and ecologically hostile, and the insatiable quest to obtain them often results in civil unrest, which is why they are often called “conflict minerals. Unfortunately, these elements, with their unique magnetic and catalytic properties, are without viable substitutes.

This is why microbes are recruited to help, in a technique known as biomining.

“Microbes can be specific in the types of elements they bind, and they allow us to remove large amounts of environmentally damaging chemicals,” like cyanides, traditionally used to leach elements from rocks, ”explained Charles Cockell, lead author of the new study and astrobiologist at the University of Edinburgh. “These days, we can even design them to be better miners. “

These microbes work their magic by producing sugars that bind to REEs. This causes the elements to concentrate, which facilitates the extraction.

To determine if bioexploitation is possible Earth, an experiment was set up in the International Space Station – a unique laboratory in which microbes can be exposed to microgravity andgravity conditions. This change in severity could affect the ability of microbes to perform their tasks was a distinct possibility, as such conditions “are known to influence microbial growth and metabolic processes,” according to the study.

“Low gravity is known to reduce sedimentation of microbes and thus reduce the mixing and flow of nutrients to microbes and wastes away from them,” Cockell said. “We can therefore expect that this will indirectly influence the growth of microbes and their interaction with rocks, and therefore their ability to biominer these rocks.”

Three different bacteria were used in the experiment: Sphingomonas desiccabilis, Bacillus subtilis, and Cupriavidus metal durans. These tests were commissioned by the European Space Agency as part of his BioRock experience, which was carried out on the ISS in 2019. The aim of the project was to see if microbes could leach an assortment of REE from basalt – a good analogue for materials found on the Moon and Mars.

The authors measured the extraction efficiency of microbes when exposed to three different conditions: microgravity, Mars gravity, and Earth gravity. To do this, ISS astronauts placed the microbes in a miniaturized biomining reactor called KUBIK.

“It’s an incubator that controls the temperature, but it also contains a spinning ring – a centrifuge,” Cockell explained. “We put our biomining reactors in the ring and spun them at exactly the right speed to simulate the gravity of Mars and Earth – Earth’s gravity being a ‘control’ experiment to make comparisons. “

Of the three bacterial species, only one, S. desiccabilis, has shown an ability to leach rare earths from basalt rock under all conditions. This bacterium did not appear to be bothered by any of the three gravitational environments, showing an extraction efficiency of 70% for cerium and neodymium. The other two bacteria showed very poor performance or no ability at all when exposed to one of the experimental conditions.

As to why S. desiccabilis did so well when his microbial comrades didn’t, Cockell said his team thinks it’s because this bacteria produces “a lot ofedited sugars that have many binding sites on them that bind theearth elements. “The other microbes didn’t do that, he said, adding,” We wondered if other microbes might be stimulated to biomining by the stressful conditions of lack of nutrients in microgravity – it is why we sent them – but microgravity didn’t change their ability or allow them to make biomin. “

The new research shows that specific microbes (there could be more, or, if not, scientists could produce genetically modified versions) will likely function as REE extractors in space. Needless to say, these microbes would die if exposed to the elements, so this imagined refining process will require smart technologies. Cockell envisions gas and fluid-filled bioreactors near lunar habitats, on Mars, and even on asteroids. Promising rocks would be placed in the reactor with the necessary microbes, the chamber sealed and pressurized, and, here– you have started the process of biomining.

Cockell said it was important to point out that his team is not proposing to do space mining and bring the materials back to Earth.

“At the moment it is not economically viable,” he said. “However, biomin and other forms of mining can be used to provide the building blocks necessary for a long-term human presence in space. Our experiment explored and demonstrated the potentially important role of microbes in facilitating human expansion in space.

The authors will now turn to an exciting experiment, called BioAsteroid, which launches on the ISS in December. The experiment will use a meteorite material as a substitute for the asteroid rock, as well as fungi with a propensity to extract rocks. BioAsteroid will also involve exposure to microgravity conditions, to assess the viability of using fungi for asteroid bio-extraction.