3D biocement printing: scaling up living mineral structures

Abstract Biocementation via microbially induced calcium carbonate precipitation (MICP) provides a biologically mediated approach for producing inorganic materials, with reduced embodied energy, using bacterial metabolism to trigger mineral formation under ambient conditions. Yet the scale-up of current MICP-based building materials is constrained by fabrication techniques that restrict control over the geometry and material performance of large structures, limiting their application as building materials. Here, we present a 3D biocement printing (3DBioP) process and bio-ink for extrusion-based additive manufacturing of inorganic materials at the decimeter scale. By embedding Sporosarcina pasteurii cells in bio-inks and printing porous structures, we enable controlled biocementation that enhances interlayer cohesion and overall mechanical performance at scales of tens of centimeters. We demonstrate that mineralization efficiency is consistent with transport-limited, reaction–diffusion-controlled precipitation modulated by surface area exposure and geometric porosity, allowing the tuning of macroscale properties through microscale design. Our results indicate that MICP enhances the printed structures and mitigates extrusion-printing issues that limit scaling, including weak interlayer adhesion and shrinkage. This work bridges the gap between biological and digital fabrication, establishing a pathway towards geometrically scalable, programmable, and low-embodied energy mineral materials.