This paper has presented a mini review of previously published articles dealing with bio-cement production using enzyme-induced calcite precipitation (EICP) technique. EICP is a biological, sustainable, and natural way of producing calcite without the direct involvement of microorganisms from urea and calcium chloride using urease enzyme in water-based solution with minimum energy consumption and eco-friendly. Calcite is a renewable bio-material that acts as a binder to improve the mechanical properties of soils like strength, stiffness, and water permeability. EICP has many real applications such as fugitive duct control with low cost comparing with water application or pouring, self-healing cracked concretes, and upgrade or change the low-volume road surfaces that are difficult for road constructions. The crystal structure of finally produced calcium carbonate (CaCO3), calcite is affected by the source of calcium ion; the calcite produced from calcium chloride has a rhombohedral crystal structure. The urease enzyme used for EICP applications could be produced in a laboratory-scale from different plant species, bacteria, some yeasts, fungi, tissues of humans, and invertebrates. Nevertheless, urease enzyme produced from jack beans has showed urease enzyme activity around 2700-3500U/g, and the tendency to replace the urease enzyme found in the global market. All urease enzymes have 12-nm size, and this smaller size makes EICP preferable for all types of soil or sands including fine and silt sands.

Contemporary reinforced concrete structures suffer from the drawback of developing micro-cracks during their service due to causes related to shrinkage and fatigue. This may compromise their technical and functional serviceability due to the possible reduction in durability which may lead to a decrease in load carrying capacity of the structure. In recent years, experimental studies on biomineralization or biocementation have shown a potential to address this issue. Biocementation is the process in which microorganisms induce the production of calcium carbonate which can improve self-healing capabilities by filling the micro-cracks and pores in the structures, similar to the traditional lime-based materials. The most used pathway of biocementation is urea hydrolysis, which is brought about by the urease enzyme secreted by ureolytic bacteria. Although there have been numerous laboratory-scale studies that have yielded positive results, the widespread adoption of this technology in practical applications is still hindered by a range of constraints. The information about the solutions to resolve these limitations is fragmented and dispersed throughout the literature. This review aims to compile state-of-the-art knowledge in one place. This article provides a detailed assessment of the challenges in the application of biocementation and suggests strategies to overcome the obstacles that hinder its use in construction projects.