Researchers Uncover Mineral Modification Through Biology – Zoo House News

The biochemical process by which cyanobacteria extract nutrients from rocks in Chile’s Atacama Desert has inspired engineers at the University of California, Irvine to think of new ways microbes could help humans build colonies on the Moon and Mars .

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 gain a detailed understanding of how microorganisms modify both naturally occurring minerals and synthetically produced nanoceramics. A key factor, according to the scientists, 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, the subject of a recent article published in the journal Materials Today Bio, could point the way for new biomimetic mining methods. The authors also said they see the results as a step towards using microorganisms in large-scale 3D printing or additive manufacturing on a scale useful in construction in harsh environments like those on the Moon and Mars.

“Through a biological process that evolved over millions of years, these tiny miners excavate rock and extract the minerals essential to the physiological functions, such as photosynthesis, that enable their survival,” said corresponding author David Kisailus, UCI Professor of Materials Science and Engineering. “Could humans use a similar biochemical approach to extract and manipulate the minerals we find valuable? This project put us down that path.”

The Atacama Desert is one of the driest and most inhospitable places on Earth, but Chroococcidiopsis, a cyanobacterium found in gypsum samples collected there by the Johns Hopkins team, “has evolved the most amazing adaptations to survive its rocky habitat said co-author 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, the researchers found clues to the microbes in the gypsum by observing how the minerals it contained were transformed.

“Cyanobacteria cells promoted the dissolution of magnetite and the solubilization of iron by producing abundant extracellular polymeric substances, resulting in the dissolution and oxidation of magnetite to hematite,” DiRuggiero said. “Production of siderophores [iron-binding compounds generated by bacteria and fungi] was enhanced in the presence of magnetite nanoparticles, suggesting that they are used by the cyanobacteria to extract iron from magnetite.

Kisailus said the way the microorganisms process metals in their desolate home made him think about our own mining and manufacturing practices.

“When we mine for minerals, we often end up with ores, which can present a challenge for extracting valuable metals,” he said. “We often have to subject these ores to extreme processing to turn them into something valuable. This practice can be financially and environmentally costly.”

Kisailus said he’s now considering a biochemical approach that uses natural or synthetic analogues to siderophores, enzymes and other secretions to manipulate minerals where only a large mechanical crusher currently works. And from here he said there might also be a way to get microorganisms to use similar biochemical abilities to produce an engineered material on demand in less than convenient places.

“I call it lunar shaping instead of terraforming,” said Kisailus. “If you want to build something on the moon, instead of bearing the expense of having humans do it, we could have robotic systems 3D printed media and then have the microbes reconfigure it into something valuable. This could be done without endangering human life.”

He added that people don’t always have to use Edison’s approaches to figure out how to do things.

“This is the main topic of my laboratory for biomimetics and nanostructured materials. Why try to reinvent the wheel when nature has perfected it over hundreds of millions of years?” said Kisailos. “We just have to extract the secrets and blueprints for what nature does and apply or adapt them to what we need.”

This project was funded by the Army Research Office and supported by instruments provided by the Department of Energy’s Office of Science. The research team also included Wei Huang, a postdoctoral fellow in Kisailus’ laboratory group; Taifeng Wang, Ph.D., who recently graduated from UCI and is now employed by Intel; and Cesar Perez-Fernandez in the Department of Biology at Johns Hopkins University.