The 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 contributed to the study which has been published in Scientific Reports.
What sets this study apart is not just the biological feat itself, but the quality and origin of the mineral formed. Under high-CO2 conditions – specifically, at concentrations over 470 times those found in the atmosphere – B. megaterium shifted its metabolic strategy. Using an enzyme called carbonic anhydrase, it converted CO2 into bicarbonate, which then reacted with calcium ions to form solid calcite. Astonishingly, 94% of the resulting mineral was derived directly from CO2, not from nitrogen-based compounds like urea.
“We know that dozens of bacteria have the potential to mineralise crystals”, says Dimitrios Terzis, corresponding author, Research and Teaching associate at EPFL’s Soil Mechanics Laboratory and co-founder of Medusoil SA. “However, what is unique about our work is that we showcase this can be done by directly using CO2. The potential that lies ahead is huge, and our teams can’t wait to upscale and maximize it.”
The research team: Pamela Principi, Margherita Cappa, Camilla Perego, Dimitrios Terzis © SUPSI 2025 – Claudia Cossu
This biological duality is rare. B. megaterium possesses two metabolic pathways to induce mineral formation: ureolysis, which depends on nitrogen compounds, and carbonic anhydrase activity, which uses CO2 directly. While the former has long been studied in the context of microbially induced calcite precipitation (MICP), it produces unwanted byproducts such as ammonia. The latter, by contrast, offers a cleaner route – capturing CO2 and converting it into solid mineral without toxic residues.
“This study shows how environmental microbiology, when combined with advanced laboratory techniques, can reveal mechanisms that would otherwise remain hidden” says Pamela Principi, researcher at SUPSI. “The use of C13-labelled urea was key to tracing the origin of the carbon in the mineral, allowing us to quantify the microbial pathways with precision. It’s a great example of how multidisciplinary approaches – bridging microbiology, geochemistry, and materials science – can lead to impactful discoveries”.
Small microbes, big potential
As conversations about climate action shift from carbon offsetting to emission prevention at the source, this research points to a new path forward – especially for industries like construction and materials manufacturing, which are among the largest direct emitters of greenhouse gases. By embedding carbon into mineral form, this microbe opens the door to bio-based, carbon-sequestering binders, and even conservation-grade materials for building and monument restoration.
This natural mechanism offers a tangible way to harness biology for climate-positive outcomes such as capturing CO2 at emission points, stabilising soils or enhancing the durability of infrastructure. “Medusoil has the know-how to operate bioreactors and scale up microbial production with field-ready solutions”, says Dimitrios Terzis.
“This study shows that despite challenges like the high concentration of CO2 needed and the fact we have to vary its purity levels, critical parameters can be effectively controlled using conventional biotechnology. We’re confident we can tune our recipes and growth conditions to bring B. megaterium to industrial deployment.”
