Effects of Chloride, Sulfate and Magnesium Ions on the Biomineralization of Calcium Carbonate Induced by Lysinibacillus xylanilyticus DB1-12

Abstract

Microbially-induced calcium carbonate precipitation (MICP) has been studied extensively. However, the effect of different sources of magnesium ions on calcium carbonate biomineralization has rarely been examined. In this study, Lysinibacillus xylanilyticus DB1-12 bacteria isolated from petroleum samples were used to biomineralize calcium ions under the action of different sources of magnesium (magnesium chloride and magnesium sulfate). The results show that calcium ion precipitation ratios were much higher in MgSO₄ group experiments than in the MgCl₂ group (p < 0.01). The mineral phases in the MgCl₂ group experiments were the same as those in MgSO₄ group at each Mg/Ca ratio. Minerals with a ‘twisted’ shape were much more common in the MgSO₄ group; the protein secondary structures hidden in minerals were much more abundant in the MgCl₂ group, and the activation energy of biotic monohydrocalcite at a Mg/Ca ratio of 11 was also much higher in the MgCl₂ group than in the MgSO₄ group. The main reasons for these differences are closely related to the lower magnesium content and the more common protein secondary structures in the monohydrocalcite in the MgCl₂ group. The shift of Mg1s XPS spectra suggests that the chemical interactions occurring on the monohydrocalcite surfaces in the MgCl₂ group were different from those in the MgSO₄ group. The δ¹³C_PDB values of the biominerals in the MgSO₄ group are in the range of −16.93 to −18.87‰, lower than those in the MgCl₂ group (-15.77 to −18.69‰). The morphology of L. xylanilyticus DB1-12 became deformed and some rod-shaped protrusions developed on the cell surface during the process of biomineralization. This study not only contributes to the understanding of biomineralization mechanisms generally, but is also helpful in the interpretations of paleo-environmental conditions.

Keywords:

• Lysinibacillus xylanilyticus
• Biomineralization
• Carbonate minerals
• Chloride ions
• Sulfate ions

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [41972108, 42072136, 42106144], Natural Science Foundation of Shandong Province [ZR2019MD027, ZR2020QD089, ZR2021QE125], Major Innovation Projects of Key R&D Program of Shandong Province [2019JZZY020808], Innovation and Entrepreneurship Training program for College students [202110424157, 202110424158].