Non ureolytic Microbiologically induced Calcium Carbonate Precipitation

Abstract:

By using non ureolytic bacteria of genus Bacillus, microbiologically induced calcium carbonate precipitation was achieved in mineral medium containing two different kinds of organic calcium sources. The characteristics of bacterial growth and kinetics of calcium carbonate precipitation were discussed. Sediments were characterized by X ray diffraction, thermal analysis and scanning electron microscopy. The results show that reducing the initial concentration of calcium ions is beneficial for improving the conversion ratio of organic calcium source, while altering the type of calcium source has a remarkable impact on both the kinetics of precipitation and the crystal form and morphology of calcium carbonate. Not well crystallized calcite and unstable vaterite was formed from calcium lactate and calcium glutamate medium, respectively, and higher precipitation productivity was obtained in the latter case, which was nearly 100%. The potential application of non ureolytic bacterially induced calcium carbonate precipitation in protection and remediation of concrete was validated.