Calcium carbonate precipitation by different bacterial strains

Abstract

Bacteria are capable of performing metabolic activities which thereby promote precipitation of calcium carbonate in the form of calcite. In this study, it is shown that microbial mineral precipitation was a result of metabolic activities of some specific microorganisms. Concrete microorganisms were used to improve the overall behavior of concrete. It was predicted that bacterial calcium carbonate (CaCO₃) precipitation occurs as a byproduct of common metabolic processes such as urea hydrolysis. In this study, ureolytic bacteria that were capable of precipitating calcium carbonate were isolated and further their urease activity was tested based on the production of urease. Scanning electron microscopy (SED) analysis revealed the direct involvement of these isolates in calcium carbonate precipitation. The production of calcite was further confirmed by x-ray diffraction (XRD) and energy-dispersive x-ray (EDX) analysis.

Key words: Bacteria, urease activity, microbial mineral precipitation, scanning electron microscope-energydispersive x-ray, x-ray diffraction.