Microbes in Space: Biomining Fungi Extract Metals in Microgravity | Cornell University
Microbes harvested from meteorites aboard the International Space Station are demonstrating an unexpected ability to extract valuable metals, even in the challenging conditions of microgravity, a new study reveals. The research, published January 30 in npj Microgravity, suggests these microscopic organisms could be key to future space resource extraction and potentially offer solutions for sustainable mining practices on Earth.
The collaborative project, led by Charles Cockell, professor of astrobiology at the University of Edinburgh, and Rosa Santomartino, assistant professor of biological and environmental engineering at Cornell University, examined the interaction between two organisms – the bacterium Sphingomonas desiccabilis and the fungus Penicillium simplicissimum – and L-chondrite asteroidal material. Researchers sought to understand how these microbes might unlock resources from space rocks, a crucial step toward self-sufficiency for long-duration space missions.
“This is probably the first experiment of its kind on the International Space Station on a meteorite,” said Santomartino. “We wanted to keep the approach tailored in a way, but similarly general to increase its impact. These are two completely different species, and they will extract different things. So we wanted to understand how and what, but keep the results relevant for a broader perspective, due to the fact that not much is known about the mechanisms that influence microbial behavior in space.”
The microbes function by producing carboxylic acids, carbon molecules that bind to minerals and facilitate their release. The study’s metabolomic analysis, which examined the biomolecules produced during the experiment, revealed distinct changes in microbial metabolism in space. Notably, the fungus significantly increased its production of carboxylic acids, enhancing the extraction of palladium, platinum, and other elements.
Interestingly, the research also showed that nonbiological leaching – the process of extracting elements using a solution without microbes – was less effective in microgravity than on Earth. Though, the microbial extraction remained consistent in both gravity conditions. “In these cases, the microbe doesn’t improve the extraction itself, but it’s kind of keeping the extraction at a steady level, regardless of the gravity condition,” Santomartino explained. “And this is not just true for the palladium, but for different types of metals, although not all of them.”
NASA astronaut Michael Scott Hopkins conducted the experiment aboard the ISS, while the Cornell team ran a parallel control experiment on Earth to compare results. Analysis of 44 different elements, 18 of which were biologically extracted, revealed subtle but significant differences in extraction rates depending on the metal, the microbe, and the gravitational environment.
Alessandro Stirpe, a research associate in microbiology at Cornell and co-author of the study, highlighted the complexity of the findings. “We don’t see massive differences, but there are some very interesting ones,” he said. The team observed that the extraction rate varied considerably depending on the metal being considered, the specific microbe involved, and the gravity conditions.
Beyond its implications for space exploration, the research could have terrestrial applications, including more efficient biomining in resource-limited environments or from mine waste, and the development of sustainable biotechnologies for a circular economy. Santomartino cautioned, however, that predicting the precise impact of space on microbial species remains a challenge due to the multitude of variables involved. “Bacteria and fungi are all so diverse, one to each other, and the space condition is so complex that, at present, you cannot give a single answer,” she said. “Maybe we need to dig more. To me, this is a little bit the beauty of that. It’s very complex. And I like it.”