Study on kinetics and morphology of formation of CaCO₃ crystal induced by carbonate-mineralization microbe

The bacteria cultured in our laboratory were used in this experiment. We studied on the influence of bacteria system, bacterial bodies system and bacterial secretion system on kinetics of formation of CaCO₃ crystal and morphology of this crystal. This work yielded that the concentration of bacteria solution increasing, induction time prolonged from 0 to 7.8 min correspondingly. Bacteria bodies accelerated the crystallization process. Bacterial secretion restrained CaCO₃ nucleation, and its induction time prolonged as different blended time with Ca²⁺. The result indicated that global CaCO₃ crystals were induced by bacterial secretion, and there were nucleation sites -COO^- and C = O in organic substances. Irregular surface of global CaCO₃ was converted to regular one when the action enhanced between Ca²⁺ and nucleation sites. The results are useful for engineering application, such as repairing microcrack on concrete surface, protecting old building surface and producing micron and nano calcium carbonate grains.