Researchers at the University of California, Irvine were motivated to think about new ways that microbes can help humans colonize the Moon and Mars by studying the biochemical process by which cyanobacteria absorb nutrients from rocks in Chile’s Atacama Desert. Researchers from UCI’s Department of Materials Science and Engineering and Johns Hopkins University’s Department of Biology used high-resolution electron microscopy and advanced spectroscopic imaging techniques to understand exactly how microorganisms modify both naturally occurring minerals and synthetically produced nanoceramics.
A key factor, the researchers say, is that cyanobacteria produce biofilms that dissolve magnetic iron oxide particles in gypsum rocks and then convert the magnetite into oxidized hematite. The team’s findings, which are the subject of a paper published recently in the journal Materials Today Bio, could pave the way for new biomimetic mining methods. The authors also said they see the results as a step toward using microorganisms in large-scale 3D printing or additive manufacturing at a scale useful in construction in harsh environments such as those on the Moon and Mars.
“Through a biological process that has evolved over millions of years, these tiny miners mine rocks and obtain minerals that are essential for physiological functions, such as photosynthesis, that allow them to survive,” said corresponding author David Kisailus, UCI professor of materials. science and engineering. “Could humans use a similar biochemical approach to obtain and manipulate minerals that we find valuable? This project led us down that path.”
The Atacama Desert is one of the driest and most inhospitable places on Earth, but the cyanobacterium Chroococcidiopsis, found in gypsum samples collected there by the Johns Hopkins team, has developed “the most amazing adaptations to survive in its rocky environment,” the co-author said. Jocelyne DiRuggiero, associate professor of biology at the University of Baltimore.”
Some of these properties include the production of chlorophyll, which absorbs far-red photons, and the ability to extract water and iron from surrounding minerals,” she added. Using advanced electron microscopes and spectroscopic instruments, scientists found evidence of microbes in gypsum by observing how the very minerals contained within were transformed.
“Cyanobacteria cells promoted magnetite dissolution and iron solubilization by producing abundant extracellular polymeric substances, which led to the dissolution and oxidation of magnetite to hematite,” DiRuggiero said. “Production of siderophores [iron-binding compounds generated by bacteria and fungi] was increased in the presence of magnetite nanoparticles, suggesting their use by cyanobacteria to obtain iron from magnetite.” Kisailus said how microorganisms process metals in their desolate home. thinking about our own mining and manufacturing practices.
“When we mine minerals, we often end up with ores that can pose problems for mining precious metals,” he said. “We often need to subject these ores to extreme processing to turn them into something valuable. This practice can be costly both financially and environmentally.” Kisailus said he is now considering a biochemical approach using natural or synthetic analogs to siderophores, enzymes and other secretions to manipulate minerals where only a large mechanical crusher currently works. And by leaps and bounds from there, he said, there might also be a way to get microorganisms to use similar biochemical abilities to produce engineered material on demand in less than convenient places.
“I call it ‘lunar shaping’ instead of terraforming,” Kisailus said. “If you want to build something on the moon, instead of paying the cost of having humans do it, we could have robotic systems 3D print media and then have microbes reconfigure it into something of value. That could be done without risk.” people’s lives.” He added that people don’t always have to use Edisonian approaches to figure out how to do things. “This is the main theme of my Laboratory of Biomimetics and Nanostructured Materials. Why try to reinvent the wheel when nature has perfected it over hundreds of millions of years?” Kisailus said. “We just have to get the secrets and blueprints of what nature does and apply them or adapt them to what we need.”
