The roles of amorphous phase on Ca–Mg carbonate mineralization under the action of bacteria and EPS

• Published in: Journal of crystal growth 2024-10, Vol.644, p.127841, Article 127841
• Main Authors: Zhang, Chonghong, Yang, Kai, Li, Fuchun, Zhou, Jianrong
• Format: Article
• Language: English
• Subjects: Amorphous Ca–Mg carbonate; Bacteria; Biomineralization; Extracellular polymeric substances
• ISSN: 0022-0248
• DOI: 10.1016/j.jcrysgro.2024.127841

•Bacterial cells and EPS could provide nucleation sites for ACMC.•Bacteria and EPS contributed to the stability of hydrated Mg-rich ACMC.•EPS and Mg2+ were important factors affecting the phase transition of ACMC. Amorphous Ca–Mg carbonate (ACMC) is an important precursor phase of carbonate, and it is of great significance for understanding the process of microbial induced carbonate mineralization and the synthesis of new biomimetic mineral materials. Currently, the biomineralization role of ACMC remains controversial. Therefore, this study conducted experiments on ACMC-induced mineralization under the action of bacteria and their extracellular polymeric substances (EPS). The results show that bacteria and their secretion of EPS contributed to the formation and stability of hydrated Mg-rich ACMC, and affected the polymorphism and morphology of minerals. Bacterial cells and EPS could provide nucleation sites for ACMC precipitation, and they could also be easily adsorbed or encapsulated by ACMC and mineral particles. EPS, Mg2+, or both were conducive to the formation of aqueous amorphous phase, and could stabilize ACMC through surface adsorption and incorporation. The results of this study help to reveal the biomineralization role of ACMC and promote understanding of the formation and transformation process of Ca-Mg carbonate.