A new study led by the University of California, Irvine (UCI) has argued that the biochemical process by which cyanobacteria acquire nutrients from rocks in Chile’s Atacama Desert could be employed in the future to build colonies on the moon and Mars.
By using high-resolution electron microscopy and advanced spectroscopic imaging techniques, the experts examined how microorganisms modify both naturally occurring minerals and synthetically made nanoceramics. According to the researchers, a key factor is that cyanobacteria produce biofilms which dissolve magnetic iron oxide particles within gypsum rocks, subsequently transforming the magnetite into oxidized hematite.
“Through a biological process that has evolved over millions of years, these tiny miners excavate rocks, extracting the minerals that are essential to the physiological functions, such as photosynthesis, that enable their survival,” explained study corresponding author David Kisailus, a professor of Materials Science and Engineering at UCI. “Could humans use a similar biochemical approach to obtain and manipulate the minerals that we find valuable? This project has led us down that pathway.”
Although the Atacama Desert is one of the driest and most inhospitable places on Earth, Chroococcidiopsis – a cyanobacterium found in gypsum samples – has developed “the most amazing adaptations to survive its rocky habitat,” as co-author Jocelyne DiRuggiero, an associate professor of Biology at the University of Baltimore, put it. “Some of those traits include producing chlorophyll that absorbs far-red photons and the ability to extract water and iron from surrounding minerals.”
“Cyanobacteria cells promoted magnetite dissolution and iron solubilization by producing abundant extracellular polymeric substances, leading to the dissolution and oxidation of magnetite to hematite,” she explained. “Production of siderophores [iron-binding compounds generated by bacteria and fungi] was enhanced in the presence of magnetite nanoparticles, suggesting their use by the cyanobacteria to acquire iron from magnetite.”
These findings have led the researchers ponder whether human mining and manufacturing processes could not be improved by using the help of such microorganisms. Moreover, these tiny bacteria could perhaps even be used to produce engineered materials on demand in less-than-convenient locations, such as the moon or Mars.
“I call it ‘lunar forming’ instead of terraforming,” Kisailus said. “If you want to build something on the moon, instead of going through the expense of having people do it, we could have robotic systems 3D-print media and then have the microbes reconfigure it into something of value. This could be done without endangering human lives.”
“This is the main theme of my Biomimetics and Nanostructured Materials Lab. Why try to reinvent the wheel when nature’s perfected it over hundreds of millions of years? We just have to extract the secrets and blueprints for what nature does and apply or adapt them to what we need,” he concluded.
The study is published in the journal Materials Today Bio.
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