A novel kinetic model for urea hydrolysis via enzyme-induced carbonate precipitation (EICP) process

• Developed a hyperbolic kinetic model for EICP with enzyme stabilizers. • Model predicts CaCO₃ precipitation beyond Michaelis–Menten limits. • Validated with 642 experiments (R² = 0.89; RMSE = 9.5%). • Offers a sustainable, low-carbon biocementation approach. This study develops and validates a kinetic model for urease-catalyzed urea hydrolysis in enzyme-induced carbonate precipitation (EICP). EICP utilizes urease-catalyzed urea hydrolysis to precipitate calcium carbonate (CaCO₃) efficiently, offering an eco-friendly alternative for material synthesis and process optimization. Recognizing that the concentrations of solution constituents critically affect the reaction, we investigate the kinetics of urea hydrolysis across a broad spectrum of operating conditions. A novel kinetic model, formulated using hyperbolic approximations, is introduced to predict carbonate precipitation beyond the limits of traditional Michaelis–Menten kinetics by incorporating the influence of enzyme stabilizers such as non-fat milk. Complemented by a comprehensive testing program—with continuous monitoring of pH and electric conductivity (EC)—this work provides detailed insights into the reaction chemistry and the role of stabilizers in enhancing urease activity. The experimental results, combined with an extensive literature dataset, elucidate how variations in urea, urease, and stabilizer concentrations modulate the hydrolysis process. Overall, our findings underscore the potential of EICP as a sustainable biochemical technique that contributes to ecological and environmental development by advancing low-carbon, resource-circular processes.