Calcification on mortar by live and UV-killed biofilm-forming cyanobacterial Gloeocapsa PCC73106

Microbial carbonate precipitation by phototrophic cyanobacteria in mortars enhances their durability. This study investigated the calcification by cyanobacteria Gloeocapsa PCC73106 in mortars. The calcium concentration and the pH were monitored, the carbonate precipitates were observed, and the performances of cubes were evaluated. Treatments with live cells under illumination resulted in the largest amount of precipitates, while UV-killed cells contributed to the highest compressive strength, the least water absorption and the lowest porosity. The morphology of precipitates differs greatly under different conditions. This is the first study showing that UV-killed Gloeocapsa PCC73106 can be a potential candidate for improving the performance of mortars.