BIO-INSPIRED MICROBIAL CEMENTATION: ORGANIC ADDITIVES ENHANCING BIO-BASED CONSTRUCTION MATERIALS

Microbial cementation technology based on microbially induced calcium carbonate precipitation (MICP) is gaining increased attention as a sustainable construction solution.Although extracellular polymeric substances (EPS) are known to play a crucial role in the natural biocementation process, the strategic utilization of organic matrices to enhance MICP efficiency remains insufficiently explored.Inspired by biomineralization mechanisms, this study systematically investigated cost-effective and environmentally benign organic additives (including amino acid derivatives, animal/plant-derived macromolecules, and soluble polymers) for regulating mineralization processes.Significant variations in the mechanical and microstructural properties of biocements incorporating different additives were revealed through unconfined compressive strength test combined with material characterization techniques, including Xray diffraction, thermogravimetric analysis, scanning electron microscopy, and X-ray photoelectron spectroscopy.Results demonstrated that the complexes formed through electrostatic interactions between calcium carbonate and polar functional groups in organic additives may be the primary mechanism underlying mechanical enhancement.Further analysis revealed that functional-group characteristics (type, density, and spatial configuration) synergistically interacted with the microenvironmental pH to control MICP mechanisms.Notably, polyacrylic acid, aspartic acid, and polyaspartic acid exhibited superior performance, enhancing the compressive strength of biocemented sandstone by more than 33% compared with that of the blank control group.This work established fundamental structure-function relationships for organic matrices in MICP, providing a rational design framework for developing bio-inspired construction materials with tailored properties.