The application potential of enzyme − induced calcium carbonate precipitation (EICP) in civil engineering: a systematic review

Enzyme-Induced Calcium Carbonate Precipitation (EICP) uses free or extracted enzymes to promote CaCO3 precipitation. The absence of intact microbial cells can reduce cell-related clogging and may improve access to fine pores in some materials. EICP therefore has potential for sealing pores and microcracks in cementitious materials. However, its environmental performance depends on the mineralisation pathway, reagent consumption, by-product management, and engineering conditions. In particular, urease-induced EICP requires control of NH3/NH4+ generated during urea hydrolysis. This paper systematically reviews the research progress of EICP technology, with particular attention to the distinct roles of urease (Ur) and carbonic anhydrase (CA) in carbonate mineralisation. The review covers reaction principles, influencing factors, engineering and microstructural characteristics, and enzyme kinetic models. Ur hydrolysis can increase alkalinity, whereas CA can accelerate CO2 hydration and inorganic − carbon conversion. These complementary functions provide a mechanistic basis for potential Ur − CA dual − enzyme systems. However, direct comparisons between Ur − CA systems and corresponding single − enzyme systems remain limited. Available studies show that reaction conditions affect CaCO3 precipitation kinetics, crystal − phase evolution, spatial distribution, and mineral stability. These characteristics can subsequently influence the engineering performance of treated materials. Coupled analysis of macro − micro characteristics and enzyme kinetic models provides comprehensive theoretical support for process optimisation. This paper summarises the application potential of EICP in ground improvement, erosion control, seepage control, and cementitious-material modification. It also identifies research needs related to enzyme sources, process optimisation, NH3/NH4+ management, environmental assessment, field implementation, and engineering cost. It provides a theoretical reference for evaluating the responsible application of EICP in civil-engineering materials and ground systems.