Study on the mechanism of calcium carbonate formation induced by carbonate-mineralization microbe

Carbonate-mineralization microbe (Bacillus) was chosen to study the influences of concentration of bacteria solution, bacteria body and bacterial secretion on calcium carbonate crystal formation. Results showed that the effect was stronger as the concentration of bacteria increasing; the crystals' form could not be affected by bacteria body only, but the bacterial secretion could induce the formation of polymorphic (e.g. spherical and spindle) metastable vaterite; inorganic-organic composite CaCO3 film formed under long-term effect by microbe. Based on the results of solution conductivity and FT-IR spectra of CaCO3 crystals, it could be concluded that there were electrostatic and coordination interaction between polar groups (COOH, C=O) in protein molecule and Ca2+. The results are useful for engineering application, such as repairing micro-crack on concrete surface, protecting old building surface and producing micron and nano calcium carbonate grains