Vaterite induced by Lysinibacillus sp. GW-2 strain and its stability.

Studies on the formation and stability of vaterite by bacteria in experimental systems are of great importance for understanding the mechanism by which microbes contribute to carbonate mineralization. In this study, mineralization experiments using Lysinibacillus sp. strain GW-2 were carried out for 72h under shaking conditions and aging experiments using biotic and chemically synthesized vaterite were performed for 60days in distilled water and air. Our results indicate that Lysinibacillus sp. strain GW-2 can induce the formation of vaterite with spherical morphology from an amorphous calcium carbonate precursor. Biogenic vaterite was more stable than chemically synthesized vaterite in distilled water, perhaps due to organic matter secreted by bacteria that enwrapped the vaterite and prevented it from transforming into more stable phases. Infrared spectrophotometry of biogenic and chemically synthesized vaterite confirmed the presence of organic matter in biogenic vaterite.