Investigating the urease activity of Sporosarcina pasteurii for potential usage of microbially induced calcium carbonate precipitation

Abstract

The urease activity of Sporosarcina pasteurii was investigated using different number of bacterial cells. Resting Sporosarcina pasteurii cells and 500 mM urea solution were placed into the beakers to measure the change in electrical conductivity of the solution. The electrical conductivity values were varied between 0.382 mS/m and 6.224 mS/m for 10 min. The highest electrical conductivity was measured for addition of the largest number of cells (10*109) to the solution. Resting Sporosarcina pasteurii cells and 500 mM urea and 500 mM CaCl2 solution were also placed into the beakers to observe and evaluate microbially induced CaCO3 precipitation. The amount of microbially induced CaCO3 precipitation was changed between 4 mg and 28 mg in the experiments for ten minutes. The highest amount of CaCO3 precipitation was observed in beaker with the highest number of cells (28 mg) than in those with the smallest number of cells (4 mg). Hence, the amount of microbially induced CaCO3 precipitation was increased in direct proportion to the cell number in the beakers. The experiments suggest that the urease activity S. pasteurii is depended on the number of cells and more cells of S. pasteurii leads more microbially induced CaCO3 precipitation in a short time period.