In situ mineral formation on a plate for direct and efficient screening of bacteria suitable for biocementation

Abstract

Microbially-induced carbonate precipitation (MICP) using a urea-hydrolyzing enzyme (urease) is a next-generation, environmentally friendly cementation technique. The isolation of excellent urease-producing bacteria for MICP is essential for establishing this technique. We have demonstrated a highly effective screening method for identifying promising bacteria suitable for MICP. In our selective plate, MICP-positive bacteria formed a CaCO3 halo around the colony on the plate, which was clearly distinguishable. Furthermore, we found that the CaCO3 formation activity of each bacterium was strongly correlated with the strength of the solidified sand samples. This technique is a novel approach for screening bacteria suitable for biocementation or MICP.