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Microbially induced carbonate precipitation as an innovative technology for achieves efficient Sr2+ bioremediation

Year: 2025

Type: article

Abstract: Microbes have demonstrated remarkable potential for Sr 2+ bioremediation under both laboratory and in situ conditions. However, the mechanism for efficient biological removal of toxic elements remains elusive. This study systematically investigated the efficacy and underlying mechanisms of Sr 2+ immobilization through microbially induced carbonate precipitation (MICP) using Sporosarcina pasteurii in a simulated contaminated system. Experimental results revealed that the strain achieved simultaneous and efficient immobilization of both Sr 2+ and Ca 2+ within 72 hours, with removal efficiencies exceeding 99.95%. Solution chemistry analysis identified high concentrations of carbonate and bicarbonate ions, generated through bacterial ureolysis, as the key drivers of the efficient precipitation process. XRD, EDS, and XPS analyses confirmed the incorporation of Sr 2+ into calcite and strontianite crystal lattices through isomorphic substitution. Intriguingly, the Sr/Ca molar ratio (0.4-0.6) in early-stage precipitates was substantially different from that in the initial solution. Complementary analyses using FTIR and 3D-EEM fluorescence spectroscopy further demonstrated that bacterial-secreted organic matter selectively regulated the preferential precipitation of Ca 2+ . As a result, the strain's exceptional mineralization capacity effectively compensated for this preferential effect, ensuring efficient Sr 2+ immobilization. This study demonstrates the application advantages of microbes in MICP technology, providing critical insights for the remediation of radioactive contamination as well as a promising strategy for carbon sequestration of microbe-derived organic matter. • Sporosarcina pasteurii demonstrates highly efficient immobilization of both Sr 2+ and Ca 2+ ions, achieving removal rate greater than 99.95%; • The superior Sr 2+ removal rate is primarily attributed to its efficient induction of high concentrations of carbonate and bicarbonate; • Sr 2+ is predominantly immobilized within the crystal lattice of either calcite or strontianite; • Co-precipitation of CaCO 3 with microbially derived organic matter facilitates long-term stabilization

Source: New Biotechnology

DOI: 10.1016/j.nbt.2025.10.012

Authors: Zhimeng Su, Ting Chen, Fuchun Li, Xuelin Li, Fei Zhang, Yin Yi