Bacteria-induced facile biotic calcium carbonate precipitation

Microbial induced calcium carbonate precipitation (MICP) is a widespread phenomenon in nature. In this paper, Bacillus mucilaginosus producing carbonic anhydrase (CA) was studied to synthesize biotic CaCO3 by capture CO2 in the air. Then the growth of the microorganism under different temperatures, initial pH values and Ca2+ concentrations were studied to determine the optimal mineralization reaction conditions. Furthermore, the mechanism of microbial mineralization was revealed by the change of calcification rate and the analysis of precipitates. The results showed that the bacteria played an important role in the nucleation and growth of biotic CaCO3. CA could accelerate the hydration of CO2 to produce HCO3- and then generate CO32- in alkali solution, which could react with Ca2+ to form biotic CaCO3 precipitation.