Effects of different calcium sources on the mineralization and sand curing of CaCO₃ by carbonic anhydrase-producing bacteria

Abstract

The deposition and dissolution of calcium carbonate can be affected by the action of biological factors, such as microbial-induced carbonate precipitation (MICP). Bacillus spp. has been isolated and applied to prevent soil erosion, increase the stability of slopes, dikes and dunes. However, previous studies have been always limited to a single calcium source (CaCl₂) to evaluate the roles of bacteria, and the deposition and curing effect has not yet been quantified. Here, we designed deposition experiments to determine the effect of Bacillus cereus with different calcium sources and applied it to sand curing to measure the amount of deposition and curing. The results demonstrated that vaterite was produced when the Bacillus cereus participated. Also, more deposition was produced in the Ca(CH₃COO)₂ and CaCl₂ groups, but the Ca(NO₃)₂ group showed optimal curing effects in the sand curing test due to the denser and more uniform deposition. This research will provide an important reference for the design and application of microbial-induced carbonate precipitation.