These microbes can help future Martians and moon dwellers extract minerals

Microbes can be the friends of future colonists who live on Earth on the Moon, on Mars, or elsewhere in the solar system and aim to create self-contained homes.

Colonists in space, like people on Earth, will need so-called rare earth elements, which are essential to modern technologies. These 17 elements, with frightening names like yttrium, lanthanum, neodymium and gadolinium, are hardly dispersed in the earth’s crust. Without the rare earth elements, we wouldn’t have some of the lasers, metal alloys, and strong magnets used in cell phones and electric cars.

But field extraction today is a difficult process. You have to crush tons of ore, then extract the tiny remains of these minerals using chemicals that leave rivers of toxic wastewater behind.

Experiments aboard the International Space Station have shown that a cleaner, more efficient method could work in other worlds: letting bacteria do the complicated job of separating rare earth elements from rocks.

“The idea is that biology essentially catalyzes a reaction that could happen very slowly without biology,” said Charles S. Kockell, professor of astrobiology at the University of Edinburgh.

On land, these bio-mining technologies are already used to produce 10 to 20 percent of the world’s copper and also in some gold mines; Scientists have identified microbes that help filter rare earth elements from rocks.

Dr Kukkell and his colleagues wanted to know if these microbes would still live and function effectively on Mars, where the force of gravity on the surface is only 38% of Earth, or even without gravity. So they sent some of them to the International Space Station last year.

The results, published Tuesday in Nature Communications, show that at least one type of this bacteria, a type called Sphingomonas desiccabilis, is not disturbed by various gravitational forces.

In the experiment, he called Biorock, 36 samples were launched into orbit in matchbox-sized containers with slices of basalt (a common rock made from cooled lava). Half of the samples contained three types of bacteria. The others contained only basalt.

On the space station, Luca Parmitano, an astronaut with the European Space Agency, placed some of them in a fast-spinning centrifuge to simulate the gravity of Mars or Earth. Other samples experimented with the free floating environment of space. Additional control experiments were carried out in the field.

After 21 days, the bacteria were killed and the samples were sent back to Earth for analysis.

For two of the three types of bacteria, the results were disappointing. But S. desiccabilis increased the amount of rare earth elements extracted from basalt almost twice, even in a zero gravity environment.

“It surprised us,” said Dr Kokkil, explaining that without gravity, there is no heat transfer which normally moves bacteria waste and replenishes nutrients around cells.

“You could then assume that microgravity would prevent the microbes from biomining or that they would pressure them to the point that they wouldn’t do biomining,” he said. “We actually didn’t notice any effect.”

The results were a little better for the lower gravity of Mars.

Payam Rasoulnia, a doctoral student at the University of Tampere in Finland who has studied bio-extraction of rare earth elements, described the results of the BioRock experiment as interesting, but noted that the yields were “very low even in earthly experiences. “

Dr Kokkil said BioRock was not designed to improve extraction. “We are really looking forward to the fundamental process that underpins this vital industry,” he said. “But that is certainly not evidence of commercial biomining.”

SpaceX’s next cargo mission to the space station, currently scheduled for December, will feature a tracking experiment called BioAsteroid. Instead of basalt, matchbox-sized containers will contain pieces of meteorite and mushroom. They will be the agents, not the bacteria, that they will test to break down rocks.

“I think eventually you can scale that up to do that on Mars,” Dr. Kokkil said.