Researchers propose using two resilient Earth microbes to create concrete-like structures from Martian regolith, potentially aiding human settlements on the Red Planet. This approach leverages biomineralization to produce building materials and oxygen on-site. The method draws from natural processes and aims to support sustainable habitats through in situ resource utilization.
Human ambitions to establish a presence on Mars face formidable challenges, including the planet's thin carbon dioxide atmosphere, low pressure—less than one percent of Earth's—and extreme temperatures ranging from -90°C to 26°C, alongside constant cosmic radiation. Traditional construction by shipping materials from Earth proves impractical due to cost and logistics. Instead, scientists advocate for in situ resource utilization (ISRU), harnessing local regolith to build shelters that double as life-supporting refuges.
Drawing inspiration from Earth's ancient microorganisms that oxygenated the atmosphere and formed durable structures like coral reefs, a new study explores biomineralization on Mars. This process involves bacteria, fungi, and microalgae producing minerals through metabolism. Focusing on harsh-environment survivors, the research highlights biocementation, where microbes generate calcium carbonate at ambient temperatures to solidify soil.
Central to this effort is a symbiotic pairing of Sporosarcina pasteurii and Chroococcidiopsis. The former produces calcium carbonate via ureolysis and secretes polymers that bind regolith. The latter, a cyanobacterium resilient to simulated Martian conditions, releases oxygen to foster a viable microenvironment and shields its partner from ultraviolet radiation using extracellular polymeric substances. Together, they convert loose Martian dust into a solid, concrete-like material.
The vision extends to 3D-printing habitats on Mars using this microbial co-culture mixed with regolith, integrating astrobiology, geochemistry, materials science, engineering, and robotics. Beyond construction, Chroococcidiopsis could bolster oxygen supplies for astronauts, while Sporosarcina pasteurii's ammonia byproduct might enable closed-loop farming or contribute to terraforming.
NASA's Perseverance rover has gathered samples from Jezero Crater, hinting at Mars's microbial past, but testing remains lab-based with regolith simulants. Challenges include replicating Martian gravity for robotics and enduring planetary stresses. With crewed missions slated for the coming decade and habitats targeted for the 2040s, accelerated research is essential. The study, published in Frontiers in Microbiology, underscores incremental progress toward making Mars habitable.
