Microbes may be friends of future colonists who live on the moon, Mars, or other parts of the solar system with the goal of building self-sufficient houses.
Like people on Earth, space colonists will need so-called rare earth elements, which are essential to modern technology. These 17 elements are rare in the earth’s crust, and their names are daunting, such as yttrium, lanthanum, neodymium and g. Without rare earths, we would not have certain lasers, metal alloys and powerful magnets for mobile phones and electric vehicles.
But mining them on the earth today is an arduous process. It needs to crush large amounts of ore and then use chemicals that leave toxic waste water to extract these metal residues.
Charles S. Cockell, a professor of astrobiology at the University of Edinburgh, said: “The idea is that biology essentially catalyzes a reaction. Without biology, the reaction would happen very slowly.
On the earth, this biological mining technology has been used to produce 10% to 20% of the world’s copper and some gold mines. Scientists have identified microorganisms that help leaching rare earth elements from rocks.
Dr. Cooker and his colleagues want to know whether these microbes will still survive and operate effectively on Mars. The gravitational force on the surface of Mars is only 38% of that of the Earth, or even no gravity at all. Therefore, they sent some of them to the International Space Station last year.
The results, published in the journal Nature Communications on Tuesday, showed that at least one of these bacteria, called Sphingomonas, was not bothered by gravity.
In the experiment called BioRock, 36 samples were placed in a box-sized container containing matching basalt flakes (common rock made from cooled lava) for orbiting. Half of the samples contained one of three types of bacteria. Others only contain basalt.
At the space station, European Space Agency astronaut Luca Parmitano (Luca Parmitano) places some of them in a centrifuge and spins them at a speed that mimics the gravity of Mars or the Earth. Other samples experienced a free-floating space environment. Other control experiments were carried out on the ground.
After 21 days, the bacteria were killed and the samples returned to Earth for analysis.
For two of the three types of bacteria, the results were disappointing. However, even in a zero-gravity environment, dried raisin bacteria increased the amount of rare earth elements extracted from basalt by approximately two times.
Dr. Cooke said: “This surprised us.” He explained that without gravity, convection usually does not take away bacterial waste and replenish the nutrients around the cells.
He said: “Then, people might think that microgravity will prevent microorganisms from biological mining, or put microbes under pressure, making them unable to conduct biological mining.” “In fact, we don’t see any impact at all.”
At lower Martian gravity, the results are even better.
Payam Rasoulnia, a PhD student at the University of Tampere in Finland, studied the biological mining of rare earth elements. He said that the results of the BioRock experiment were very interesting, but he pointed out that even in ground experiments, the output was very low.
Dr. Cooke said that BioRock is not designed to optimize extraction. He said: “We are studying the basic processes that support bio-mining.” “But of course this is not a demonstration of commercial bio-mining.”
The next SpaceX cargo mission currently scheduled for December will conduct a follow-up experiment called BioAsteroid. Matchbox-sized containers will replace meteorites and fungi instead of basalt. Instead of bacteria, they will be their reagents for testing the decomposition of rocks.
Dr. Cooke said: “I think, eventually, you can scale up to observe on Mars.”