Crystal transformation and self-assembly theory of microbially induced calcium carbonate precipitation

Microbially induced calcium carbonate precipitation (MICP) is ubiquitous in the earth's lithosphere and brings the inspiration of bionic cementation technology. Over recent years, MICP has been proposed as a potential solution to address many environmental and engineering issues. However, the stability of cemented precipitations generated via MICP technology, especially the characteristics and change mechanism of crystal forms, is still unclear, which substantially hindered the understanding of biomineralization and prohibited the application and upscaling of MICP technology. Here, Sporosarcina pasteurii was selected as a model microbe to induce calcium carbonate mineralization in a series of standard nutrient solutions. The authors studied the process of precipitation from amorphous calcium carbonate to calcite crystal form and revealed the assembly behavior and mechanism of precipitations by FTIR, SEM, TEM and EDS. In the two crystal forms of induced calcium carbonate, the relative position and content of C, O, N, P and Ca elements were only slightly different. The molecular attachment and structural match of organic matrix made the crystals form change. Finally, a self-assembly theory was proposed to MICP, and it provided a solid theoretical basis for the technical specification of MICP technology in engineering application.

Automated summary

MICP technology is a potential solution for addressing environmental and engineering issues. The study reveals that molecular attachment and structural match of organic matrix are key factors causing changes in the crystal forms of calcium carbonate precipitation.