HMN 2025: What is the multitasking microbe that turns CO? into minerals

At greater than 470 occasions the atmospheric focus of CO?, a humble soil bacterium does one thing extraordinary: it turns gasoline into stone.

In the longer term, may the partitions of our homes be partly comprised of CO?? Researchers from EPFL’s Soils Mechanics Laboratory, the University of Applied Sciences and Arts of Southern Switzerland (SUPSI) and the EPFL start-up Medusoil SA have demonstrated that Bacillus megaterium—a resilient and versatile microorganism generally present in soil, freshwater and marine environments and even plant surfaces—can mineralize carbon dioxide (CO?) into calcium carbonate (CaCO?), the mineral that varieties limestone and marble. Their study has been published in Scientific Reports.

What units this study aside isn’t just the organic feat itself, however the high quality and origin of the mineral fashioned. Under high-CO? situations—particularly, at concentrations over 470 occasions these discovered within the environment—B. megaterium shifted its metabolic technique. Using an enzyme referred to as carbonic anhydrase, it transformed CO? into bicarbonate, which then reacted with calcium ions to kind strong calcite. Astonishingly, 94% of the ensuing mineral was derived instantly from CO?, not from nitrogen-based compounds like urea.

A clear path to strong minerals

“We know that dozens of micro organism have the potential to mineralize crystals,” says Dimitrios Terzis, corresponding writer, Research and Teaching affiliate at EPFL’s Soil Mechanics Laboratory and co-founder of Medusoil SA. “However, what is exclusive about our work is that we showcase this may be carried out by instantly utilizing CO?. The potential that lies forward is big, and our groups cannot wait to upscale and maximize it.”

This organic duality is uncommon. B. megaterium possesses two metabolic pathways to induce mineral formation: ureolysis, which is determined by nitrogen compounds, and carbonic anhydrase exercise, which makes use of CO? instantly. While the previous has lengthy been studied within the context of microbially induced calcite precipitation (MICP), it produces undesirable byproducts comparable to ammonia. The latter, in contrast, provides a cleaner route—capturing CO? and changing it right into a strong mineral with out poisonous residues.

“This study reveals how environmental microbiology, when mixed with superior laboratory methods, can reveal mechanisms that might in any other case stay hidden” says Pamela Principi, researcher at SUPSI. “The use of C¹³-labeled urea was key to tracing the origin of the carbon within the mineral, permitting us to quantify the microbial pathways with precision. It’s an amazing instance of how multidisciplinary approaches—bridging microbiology, geochemistry, and supplies science—can result in impactful discoveries.”

Small microbes, large potential

As conversations about local weather motion shift from carbon offsetting to emission prevention on the supply, this analysis factors to a brand new path ahead—particularly for industries like building and supplies manufacturing, that are among the many largest direct emitters of greenhouse gases. By embedding carbon into mineral kind, this microbe opens the door to bio-based, carbon-sequestering binders, and even conservation-grade supplies for constructing and monument restoration.

This pure mechanism provides a tangible solution to harness biology for climate-positive outcomes, comparable to capturing CO₂ at emission factors, stabilizing soils or enhancing the sturdiness of infrastructure. “Medusoil has the know-how to function bioreactors and scale up microbial manufacturing with field-ready options,” says Dimitrios Terzis.

“This study reveals that regardless of challenges just like the excessive focus of CO? wanted and the very fact we’ve to range its purity ranges, essential parameters will be successfully managed utilizing standard biotechnology. We’re assured we will tune our recipes and progress situations to carry B. megaterium to industrial deployment.”