Could Bacteria Turn Martian Dust Into Concrete?

Will future Mars habitat questions be solved with biology?

Shipping bricks to Mars is a nonstarter. Every pound launched from Earth carries a huge cost, and if we were to build a crewed outpost on the Red Planet, we would need a lot more than a few bags of mortar. That’s why some engineers keep coming back to the same idea: use what’s already there. Mars has plenty of regolith. This means the real trick is finding an efficient way to bind those loose grains into something that can hold its shape.

A new perspective article in Frontiers in Microbiology argues that the binder might actually come from biology. Instead of firing regolith into ceramic bricks or hauling industrial ingredients across space, the authors propose using microbes to precipitate local minerals that act like a natural cement, then feeding that living “construction chemistry” into robotic 3D printers.

“We envision this bacterial co-culture mixed with Martian regolith as feedstock for 3D printing on Mars,” state the researchers. “At the intersection of astrobiology, geochemistry, material science, construction engineering, and robotics, this synergistic system could revolutionize the potential for construction on the Red Planet, redefining the design-for-manufacturing on Mars.”

The team suggests a tough cyanobacterium be used with a urease-powered bacterium, known on Earth in biocement research. The less glamorous part is the ingredient meant to keep the system running: astronaut urine.

The “cement” that bacteria can grow

On Earth, scientists and engineers have spent years testing microbially induced carbonate precipitation (MICP), a process where microbes help form calcium carbonate (CaCO3), the same family of minerals found in limestone and seashells. In construction-minded experiments, CaCO3 can lock grains of sand or soil together, stiffen surfaces, and even help seal cracks in materials.

The Frontiers authors focus on a version of this that runs fast and produces strong mineral bonds. Ureolysis, a bacteria that breaks down urea, shifted local chemistry in a way that encourages carbonate minerals to form. If calcium ions are available, CaCO3 can precipitate right where it’s needed — around grains of regolith — acting like a microscopic mortar.

Mars is hostile to most life as we know it: thin air, brutal radiation, extreme cold, just to name a few things. For this reason, the paper proposes a co-culture, two organisms that might help each other survive while also improving cement formation.

The suggested pairing is Chroococcidiopsis (known for extreme-environment toughness) and Sporosarcina pasteurii (a model organism for ureolysis-driven biocement). Space-exposure work has tested dried Chroococcidiopsis cells in Mars-like conditions outside the International Space Station via ESA’s EXPOSE-R2 facility, tracking survival and damage after long exposure to UV and Mars-like atmosphere.

Yes, they bring up urine—here’s why

“Waste” is a loaded word in closed systems. A Mars habitat has to recycle almost everything, so mission planners look for loops: one process produces inputs for another.

In this proposal, astronaut urine is not a gimmick; it’s chemistry in a convenient container. The article suggests urine could provide urea (needed for ureolysis) and ions such as calcium and potassium to support microbial growth, after regolith is leached with water to make a nutrient-containing medium.

In the best-case sketch, this becomes a small, messy circle: humans produce waste; microbes use parts of that waste to harden regolith; hardened regolith becomes habitat structures that protect humans.

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Despite the optimism, the authors repeatedly flag the unknown. The effects of Martian gravity on microbial growth and biofilms remain largely untested; long-duration reduced-gravity experiments are hard to do. The behavior of this co-culture under stacked stressors is still speculative. The authors also point out the lack of empirical evidence for long-term co-culture stability under Mars constraints and lay out practical engineering problems: abrasive regolith, clogging from precipitation, biofilm detachment, gas exchange, water handling, and scaling the bioreactor without turning it into a maintenance nightmare.

For now, this work reads like a blueprint pinned to a lab wall: plausible pathways, named organisms, and a list of obstacles that can guide experiments. The next steps are less cinematic than “printing a Mars habitat,” but more decisive such as testing co-cultures in regolith simulants, measuring strength and durability, and proving the system doesn’t collapse after weeks or months.