A novel approach to accelerate bacterially induced calcium carbonate precipitation using oxygen releasing compounds (ORCs)

In the present study, a mixture of oxygen releasing compounds (ORCs) was designed in an attempt to continuously supply dissolved oxygen (DO) in the oxygen-limiting conditions and evaluate bacterially induced calcium carbonate (CaCO3) production. The biomineralization of CaCO3 was adversely affected in the presence of calcium peroxide (CP) and zinc peroxide (ZP), whereas urea-hydrogen peroxide (UP) and magnesium peroxide (MP) were found to be significant on enhancing the biosynthesis of CaCO3. The optimal values for UP and MP obtained from central composite face-centered (CCF) were 1800 mg/L and 8.3 mg/L, respectively. As compared to the control samples, the bacterially induced CaCO3 precipitation was not only enhanced but also accelerated when the optimum concentrations of ORCs were supplemented in the fermentation media. Moreover, the morphology of the precipitated CaCO3 was affected in the presence of ZP, while no such effect was observed when the media were supplemented with CP, UP or MP. The results of this study can be used in many natural and engineered applications such as the constructional purposes for designing a more efficient bio self-healing concrete. The other applications of this innovative technology are the removal of heavy metals, radionuclides and calcium ions contaminants from the environment.