Biokinetic modeling of ureolysis in Sporosarcina pasteurii and its integration into a numerical chemodynamic biocalcification model

A dynamic model for Sporosarcina pasteurii-mediated ureolytic biocalcification process has been proposed, which incorporates microbial growth-dependent ureolysis, equilibrium speciation of dissolved inorganic carbon (DIC), dissolved inorganic nitrogen (DIN), different sodium and calcium containing species, kinetics of gas/solution exchange (for CO2, NH3), and a dynamic charge balance. The kinetics of microbial growth and ureolysis (including parameters) were selected from a set of relevant representative models using designed batch ureolysis experiments and were incorporated into the dynamic model. The gas/solution exchange rate constants for CO2 and NH3 were assessed from independent sets of abiotic experiments while regressing their measured DIC-pH profiles or DIN-pH profiles, respectively. Subsequently, residual parameters associated with CaCO3 precipitation were estimated by calibrating one or more measured profiles (DIN, urea, Ca2 +, and pH) from the ureolytic-biocalcification experiment with the dynamic model. Bootstrap confidence intervals and sensitivity analysis of these model parameters are presented.