Enzyme-Induced Carbonate Precipitation (EICP) is an innovative technique to improve soil strength and reduce permeability. However, the use of EICP for reinforcing underwater sand beds remains largely unexplored. To advance EICP implementation in various geotechnical applications, this paper develops a model box system to investigate the effectiveness of the EICP technique in reinforcing underwater sand beds. An ''injection-extraction'' system is designed to facilitate the flow of the EICP solution through underwater sand layers. Key parameters, including conductivity, pH, and Ca2+ concentration of the solution, are measured and analyzed. Electrical resistivity tomography (ERT) is utilized to evaluate the reinforcement effect in the underwater sand bed. The permeability of the model is tested to verify the feasibility of EICP technology for strengthening underwater sands. Furthermore, scanning electron microscope (SEM) is performed to investigate the growth mechanisms of calcium carbonate (CaCO3) crystals. The results show that the permeability of the model decreases from 1.28 × 10−2 m/s to 9.66 × 10−5 m/s, representing a reduction of approximately three orders of magnitude. This verifies that the EICP technology can greatly reduce the permeability of underwater sand beds. With increasing grouting cycles, the resistivity of the underwater sand initially decreases and then increases. This variation in sand resistivity is significantly influenced by the ion concentration in the solution, resulting in marked differences in resistivity at various depths and positions within the sand. The findings from this study offer a theoretical basis for the application of EICP technology in reinforcing seabed foundations and supporting marine infrastructure such as offshore pipelines, wind turbines, and oil platforms.

EICP and geogrids are widely regarded as environmentally sustainable and effective techniques for soil stabilization. This study assesses the feasibility of combining EICP with geogrid reinforcement to improve the mechanical properties of sands. The Brazilian splitting test and particle image velocimetry were employed to investigate the effects of three independent variables-the cementation-enzyme ratio (X1), median particle size (X2), and geogrid placement (X3)-on the mechanical behavior of sand treated with both EICP and geogrid (STEG). Response surface methodology was used to assess variable interactions and optimize parameters for maximum tensile strength. The mechanism of reinforcement was further investigated through measurements of calcium carbonate content, permeability testing, ultrasonic velocity analysis, and scanning electron microscopy (SEM). Results show that the interactions between variables significantly influence the tensile strength and failure patterns of STEG. The optimal parameters (X1 = 1:1.935, X2 = 1.211 mm, X3 = 1.2 cm) achieved a tensile strength of 1.71 MPa. Compared with specimens without geogrids, STEG samples demonstrated higher peak and residual strengths. SEM results revealed substantial calcium carbonate precipitation around geogrids, enhancing interparticle bonding, increasing ultrasonic velocity, and reducing permeability. These findings highlight the potential of combining EICP and geogrids to improve the mechanical properties of cohesionless soils, offering promising applications for subgrade reinforcement.

Enzyme-induced carbonate precipitation (EICP) is a potential ground improvement method that can reduce the permeability of sands. However, the traditional mathematical models are hard to accurately predict the permeability of EICP-treated sands. In this study, the mathematical model was established for predicting the permeability of EICP-treated sands based on Kozeny-Carman equation. The effects of calcium carbonate precipitation on the porosity, tortuosity, and specific surface area of the EICP-treated sands were considered in the model. To validate the model, the bio-cemented sand column tests with different grain size distributions (coarse, medium, and fine sands) and treatment numbers (6, 8, and 10 times) were conducted. The calcium carbonate content (CCC) and permeability of EICP-treated sands were measured. The validation of the model was confirmed through a comparative analysis of theoretical and experimental results. Furthermore, the impacts of porosity, particle size, CCC, and specific surface area on the hydraulic conductivity of EICP-treated sands were analyzed. The results showed that the model can reflect the hydraulic conductivity of EICP-treated sands under different particle size distributions and degrees of cementation, demonstrating broad applicability. Parametric analysis indicated the hydraulic conductivity gradually decreases with increasing CCC and specific surface area. Conversely, the hydraulic conductivity gradually increases with increasing porosity (n) and particle size (d50), with porosity exhibiting a significantly higher sensitivity than particle size. In summary, this study contributes theoretical foundations for the practical implementation of EICP technology in reducing soil permeability.

INTRODUCTION: This study aimed to investigate the oral cecal transit time (OCTT) and its correlation with small intestinal dysbiosis in cirrhotic patients with minimal hepatic encephalopathy (MHE) and coexisting small intestinal bacterial overgrowth (SIBO). METHODS: We enrolled 110 patients with a confirmed diagnosis of cirrhosis admitted to the Department of Gastroenterology at The Affiliated Hospital of Qingdao University between December 2021 and December 2023. The lactulose hydrogen breath test was used to diagnose SIBO and to measure OCTT. Patients were stratified into 3 cohorts: a SIBO(+) MHE group, a SIBO(-) MHE group, and a non-MHE group. Duodenal mucosal biopsies were collected from a subset of 26 cirrhotic patients and 5 healthy controls for microbial analysis. RESULTS: Among the 110 cirrhotic patients, the prevalence of MHE was 53.6% (59/110). Within the MHE cohort, the prevalence of SIBO was 71.19% (42/59). The SIBO(+) MHE group exhibited a significantly prolonged OCTT compared with both the non-MHE group (P < 0.05) and the SIBO(-) MHE group (P < 0.05). At the phylum level, Proteobacteria, Firmicutes, and Bacteroidetes were the most dominant taxa. At the genus level, Rothia, Streptococcus, Escherichia, Actinomyces, Prevotella, and Pseudomonas predominated. Significant differences in the small intestinal microbiota composition were found between the SIBO-MHE group and the other 2 cirrhotic groups (P < 0.05). Patients with prolonged OCTT showed a greater relative abundance of Bacteroides, Streptococcus, Bacillus, Lactobacillus, Alphaproteobacteria, and Prevotella. DISCUSSION: Cirrhotic patients with SIBO(+) MHE demonstrate a prolonged OCTT compared with their counterparts without SIBO, indicating significant gastrointestinal dysmotility.

While microbial-induced carbonate precipitation (MICP) immobilizes heavy metals (HMs), the resulting precipitates are often susceptible to remobilization under extreme pH conditions. This study evaluated an integrated MICP-flotation technology as a sustainable strategy for recovering lead (Pb) from contaminated water and soil. By optimizing inoculation ratios, pulp pH, aeration rates, and reagent combinations, supported by molecular dynamics (MD) simulations, the study identified mechanistic drivers of recovery efficiency. While high inoculation ratios impeded Pb recovery, increased pulp pH and aeration rates significantly enhanced performance. In aqueous systems, the synergistic use of cationic collectors and foaming agents achieved a Pb recovery of 85.8%. These reagents initially maintained stability through electrostatic repulsion before increasing mineral hydrophobicity to facilitate bubble adhesion. In soil applications, untreated loess exhibited positive surface charges that repelled cationic collectors, hindering recovery. However, MICP treatment transformed Pb into cerussite (PbCO3), which possesses a negative surface charge. This shift promoted electrostatic attraction with cationic reagents, yielding a recovery efficiency of 84.5%. These findings indicate that MICP-flotation integrated technology is a sustainable approach for the recovery of HMs from complex environmental matrices.

In this study, unconfined compressive strength, calcium carbonate content, scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR) tests were conducted to study the influence of cementation solution concentration, urease concentration, enzyme gel ratio, organic material type and content on the curing effect of enzyme-induced carbonate precipitation (EICP) combined with organic materials. The results show that the organic material type has the most prominent influence, with skim milk powder demonstrating the best combined curing effect. The unconfined compressive strength and calcium carbonate content increase with the increase of urease concentration and organic material content, whereas they initially increase and then decline as the cementation solution concentration and enzyme gel ratio increase. The optimal combination of curing parameters obtained herein is a cementation solution concentration of 1.35 mol/L, a urease concentration of 100 g/L, an enzyme gel ratio of 1 & ratio;1, and a skim milk powder content of 3%. After incorporating skim milk powder, larger and massive calcium carbonate crystals are deposited between the particles of solidified desert sand, and smaller and spherical calcium carbonate crystals are deposited on the particle surfaces, effectively filling the intergranular pores while significantly reducing the number of large-sized pores and improving the pore structure. The findings of this study are expected to contribute to desertification control and infrastructure construction in desert areas.

Bacterial enzyme induced carbonate precipitation (BEICP) is an emerging biomineralization technique for soil improvement, yet the urease extraction efficiency remains insufficient for field applications. This study proposes a bacterial concentration pretreatment involving low concentrations of calcium chloride to enhance the urease extraction efficiency. A series of tests were conducted to investigate the effects of calcium ion concentration (Ccal) and pH on urease extraction efficiency. Then, the sand column treatment test was conducted to evaluate the performance of the proposed pretreatment on the biomineralized sand columns. The results show that a 5-fold increase in the urease extraction efficiency is achieved under optimal conditions (pH of 8.24 and Ccal of 0.03M), which is mainly attributed to a reduction in the volume of the bacterial suspension through flocculation induced by low-concentration calcium chloride. However, the enhancement of the unconfined compressive strength of BEICP-treated sand using the urease extracted from concentrated bacteria is limited, which may be attributed to the relatively low crystallinity of the precipitated calcium carbonate crystals and the slightly lower calcium carbonate content. This is possibly caused by the calcium ions and cavitation during ultrasonic extraction and thus producing relatively lower calcium conversion efficiency. It is worth mentioning that the bacterial concentration pretreatment for efficient urease extraction can offer a promising strategy for field applications of BEICP-treatment.

Microbially induced carbonate precipitation (MICP) is a promising ground improvement technique which has recently gained significant research attention. The magnesium-mediated bio-cementation has been proven to improve the physical and mechanical properties of cemented sand, while little focus has been pay for its underlying mechanism. This study systematically investigates the effects of different magnesium sources and magnesium-to-calcium (Mg/Ca) ratios on the MICP treatment. MICP experiments with different cementation solutions are conducted to reveal the effects of magnesium on carbonate precipitation efficiency, mineral composition, and the mechanical and hydraulic properties of bio-cemented sands. The strength and permeability of the bio-cemented sand are then assessed through UCS and variable-head permeability tests. The results show that magnesium ions not only alter the types and proportions of carbonate crystal forms, but also modify their precipitation patterns within the sand matrix, consequently influencing the macroscopic mechanical and permeability characteristics of bio-cemented sands. The synergistic application of insoluble magnesium sources with soluble calcium sources in MICP process effectively reduces retarding effects of high ion concentration on bacterial urease activity. This optimized approach significantly enhances the macroscopic mechanical performance of bio-cemented soils while maintaining favorable cementation uniformity.

Spray seeding substrate, which is a mixture of soil and seeds, is a material that is commonly used in the ecological restoration of slopes. In hilly areas of southern China, granite residual soil is widely distributed and inevitably used to prepare spray seeding substrates. However, due to the water sensitivity of granite residual soil, the spray seeding substrates when using this soil are easily washed away by rainfall, resulting in poor ecological restoration of slopes. This study proposes an anti-erosion spray seeding substrate modified by bioslurry-based Microbially Induced Carbonate Precipitation (MICP) and Xanthan Gum (XG) (referred to as bioslurry-XG hereafter). To verify the substrate’s water stability and plant growth, a series of macro- and microscopic tests were conducted. The results indicate that combining bioslurry with XG can effectively enhance the water stability of granite residual soil. This is primarily due to pore-filling by XG and CaCO3 crystals, CaCO3 cementation, and the cohesion of the XG gel network to strengthen the soil. Meanwhile, the bioslurry-XG treatment can promote the plant growth by improving soil water retention and providing nutrients (e.g., urea). The optimum parameters are: 28

Enzyme-induced calcium carbonate precipitation (EICP) is a promising low-carbon alternative for ground improvement, but the pH evolution, solute transport, CaCO3 precipitation, and hydraulic characteristics are not yet well understood. This study develops a coupled model for one-phase EICP suction-assisted grouting based on acid-base equilibrium, convection-diffusion- reaction, which is verified by sand column tests. Results indicate that urease activity is the dominant control on average calcium carbonate content (CCC) and permeability (k/k0). This model is then applied to simulate suction-assisted EICP grouting beneath a foundation using two injection strategies. Suction enlarges the Ca2+ plume and the cemented zone, while reducing peak CCC. H6T3 (6 holes and 3 times) produces a wider, moderately cemented region, whereas H3T6 (3 holes and 6 times) forms higher peak CCC near the injection holes but in a narrower band, and suction broadens the low permeability zone. Plate load results show that the ultimate bearing capacity increases from 40.2 kN for the untreated ground to 152 kN at 0 suction and 304 kN at -4 kPa suction for H6T3. Whereas the untreated ground fails in a narrow punching shear zone directly beneath the foundation, the reinforced ground has a 1% CCC contour that acts as a rigid block and transfers the plastic strain band into the uncemented soil. The bearing capacity is governed more by how far this plastic band is pushed outward than by locally higher CCC near the injection holes.

Enzyme-induced carbonate precipitation (EICP) has emerged as a promising technique for soil stabilization, notably enhancing the strength of sandy soils. However, EICP-treated sand exhibits low ductility and brittle failure behavior, limiting its application in geotechnical structures. To address this issue, this study proposes the incorporation of geogrid reinforcement to improve both the strength and ductility of EICP-treated sand. To evaluate the mechanical behavior of biocement–geogrid reinforced sand (BGRS), a series of laboratory tests, including unconfined compressive strength (UCS) tests and particle image velocimetry (PIV) tests, were conducted to investigate the influence of immersion duration in a weak-acid environment on both reinforced and unreinforced EICP-treated sand. Additionally, a digital image processing technique was employed to quantitatively analyze microstructural damage. A constitutive model under hydro-chemo-mechanical coupling was developed based on statistical damage mechanics theory. The results show that geogrid reinforcement significantly improves both the strength and ductility of EICP-treated sand. With increasing immersion time, the strength and elastic modulus of the BGRS decline progressively, accompanied by a shift in failure mode from shear failure to expansion failure. Microscopic analysis reveals that the degradation is caused by acid–base reactions and the effect of water weakening, which promote the development of internal voids and consequently reduce the cementation efficiency of EICP. Furthermore, the proposed damage constitutive model exhibits good agreement with the experimental data, effectively capturing the failure behavior of the BGRS under hydro-chemo-mechanical coupling. These findings provide useful insights for understanding and evaluating the mechanical behavior of biocement–geogrid composite systems under water weakening and weak-acid environments.

Bacterial cells are widely accepted as nucleation sites for calcium carbonate precipitation in biomineralization based on the Microbially Induced Carbonate Precipitation (MICP) process. For MICP-based in-situ biotreatment, the first problem to be solved is how to introduce and retain the bacterial cells in the soil, which involves the migration and retention of bacterial cells during the biogrouting process. Soil particle size, a key factor in determining pore throat size, can have a significant effect on the migration and retention of bacterial cells in the soil and therefore on biomineralization. To investigate the effect of particle size on the migration and retention of bacterial cells in sand and its biomineralization, two sets of tests were carried out in this study, including percolation tests and sand column treatment tests. Soil urease activity (defined as urease activity per unit mass of soil) and calcium carbonate content of the biomineralized sand were measured to comprehensively assess the migration and retention of bacterial cells in the sand. The results indicate that sands with a particle size smaller than 0.25 mm would inhibit the migration of bacteria in the sand, resulting in a nonuniform distribution of precipitated calcium carbonate and a low strength enhancement of biomineralization. On the other hand, sands with a particle size larger than 1.18 mm are unfavorable for retaining bacterial cells in the sand, resulting in low calcium conversion efficiency. Meanwhile, particle size would also affect the formation of effective calcium carbonate through interparticle contact number and interparticle pore size, and thus biomineralization.

Biomineralization technology has been proven to be a feasible and effective method for the treatment of calcareous sand in island and reef areas. In such areas, freshwater is scarce and the calcareous sand is constantly affected by the seawater environment. However, existing researches on biomineralized calcareous sand have mostly been conducted in freshwater conditions, which may be unsuitable for large-scale calcareous sand foundation treatment. Moreover, the properties of calcareous sand treated by seawater-based biomineralization technology will be different, especially for the different influencing factors on its performance, such as urease activity and chemical concentrations of cementation solution (i.e., calcium chloride and urea solution). This study aims to investigate the effects of both influencing factors on the calcareous sand treated by seawater-based bacterial enzyme-induced carbonate precipitation (BEICP) technology. Based on a series of solution tests, permeability, unconfined compression tests and scanning electron microscopy (SEM) analysis, the performance of BEICP-treated calcareous sand is clarified. Test results show that the biomineralization effect of BEICP-treated calcareous sand can be improved by reducing urease activity and increasing concentrations of seawater-based cementation solution within a certain range. Bacterial urease with higher urease activity can tolerate seawater-based cementation solution with higher chemical concentrations under the tested conditions. The optimal parameters are urease activity of 5.0 U/ml and a cementation solution concentration of 0.75 M, which contributes to improve the behaviors of BEICP-treated calcareous sand. The findings of this study can be beneficial for the application of biomineralization technology in island areas.

Microbial-induced carbonate precipitation (MICP) technique have the potential to be an eco-friendly and sustainable solution for engineering problems that has presented promise in various geotechnical applications. Despite the extensive amounts of studies about the MICP technique has been conducted recently, there are few studies on the constitutive model of MICP-treated specimens. In this study, the statistical damage constitutive model of MICP-treated specimens was established based on the statistical theory and damage mechanics theory. The model assumed that the microelement strength of bio-cemented sand obeys the log-normal random distribution and the D-P criterion. The parameters S 0 and F 0 in the constitutive model were determined and the physical significance of parameters were discussed accordingly. The reasonableness of the proposed model were verified by comparing the theoretical results and the experimental results. The evolution of the damage variable ( D ), parameter S 0 and parameter F 0 with different calcium carbonate content ( CCC ) were analyzed. The statistical damage models based on log-normal distributions was then compared with that based on Weibull distributions. The results show that the parameter F 0 and S 0 can reflect the limiting strength and brittleness of MICP-treated specimens, respectively. The damage rate accelerates with increase in cementation level, leading to larger damage values. The damage variables eventually reaches a stable value as the axial deformation increases. The proposed model can reflect the strain softening and strain hardening phenomena well, which can also represent the shear expansion and shear contraction characteristics of the volume strain curve. Overall, the research in this study provide some theoretical support for the engineering application of MICP-treated specimens.

Biopolymers and the enzyme-induced calcite precipitation (EICP) technology have been widely studied and applied in soil improvement. They each possess unique characteristics and different mechanisms of action, yet there is currently still a lack of in-depth understanding of their combined effect. Therefore, this paper utilized the combination of EICP with two types of biopolymers, namely, sodium alginate and guar gum, to reinforce Chinese standard sand. A series of physical, mechanical, and microscopic tests were conducted on the sand treated by EICP combined with different biopolymer contents. The test results show that EICP combined with biopolymer treatment can enhance the strength and impermeability of sand more evidently, and the sodium alginate exhibits a better effect than guar gum. The guar gum increases the viscosity of the reaction solution, hindering the migration of ions within it and leading to a rise in local ion concentration, which promotes the deposition of calcium carbonate. In contrast, sodium alginate formed a gel network between sand particles through ion exchange, inhibiting the deposition of calcium carbonate. EICP combined with sodium alginate/guar gum treatment can greatly reduce the proportion of large pores in sand, thus improving its pore structure. The findings of this study confirm the superiority of EICP combined with biopolymer, which is expected to provide a reference for subsequent research and practical geotechnical engineering applications.

An innovative microbial remediation protocol is proposed to overcome critical limitations of conventional microbial-induced carbonate precipitation (MICP) for concrete crack repair. The method integrates pH preconditioning of Sporosarcina pasteurii with a bioadditive-assisted crystallization strategy to address microbial inactivation under highly alkaline conditions, inefficient calcium utilization, and structural instability caused by metastable vaterite formation. Acidification to pH 5.5 preserved 78 % of urease activity at pH 12.5 by stabilizing bacterial zeta potential, while a composite bioadditive composed of polyvinyl alcohol, sodium alginate, and colloidal silica nanoparticles reduced the critical nucleation radius by 29 %, enhancing calcite crystal formation. Mechanical testing showed a 26.8 % increase in flexural strength and an 88.7 % calcium utilization rate, with durability evaluations confirming stable crack sealing over 180 thermal-humidity cycles. Field-scale application to a deteriorated underground garage demonstrated 92 % void-filling efficiency and compressive strength recovery from 28.5 MPa to 41.2 MPa. The developed protocol eliminates the need for carrier materials and reduces carbon emissions, establishing a scalable and sustainable framework for infrastructure rehabilitation. These results highlight the potential of synergistic biological and material strategies for advancing next-generation selfhealing concrete technologies.

Heavy metal pollution in landfill soil poses a dual challenge of environmental toxicity and resource depletion. Enzyme-induced carbonate precipitation (EICP) was systematically evaluated as a sustainable stabilization method for cadmium (Cd), lead (Pb), and chromium (Cr) under both solution- and soil-phase conditions. Laboratory-scale experiments demonstrated that EICP achieved over 80% removal efficiency for Cd, Pb, and copper (Cu) in solution-phase systems, while soil-phase trials focused on Cd, Pb, and Cr to simulate realistic field conditions. Optimal performance was achieved using a 1:1 molar ratio of soybean-derived urease (1.0 U/mL) to CaCl2 (0.5 M), with Cd stabilization reaching 91.5%. Vacuum-assisted filtration improved treatment uniformity by 29.2% in clay soils. X-ray diffraction identified crystalline otavite in Cd systems, while Pb and Cu were stabilized via surface adsorption. Sequential extraction confirmed that over 70% of Cd was transformed into carbonate-bound phases. Treated soils met TCLP leaching standards and reuse criteria, maintaining neutral pH (7.2–8.1) and low salinity. Compared to cement-based methods, EICP avoids CO2 release from calcination and fossil fuel use. Carbon in urea is retained as solid CaCO3, reducing emissions by 0.3–0.5 t CO2-eq per ton of soil. These findings support EICP as a scalable, low-carbon alternative for landfill soil remediation.

One-phase-low-pH method is a simple, efficient and easy-to-use biogrouting method for biomineralization based on an Enzyme Induced Carbonate Precipitation (EICP) process. This method utilizes the low-pH biotreatment solution (a mixture of urease solution and cementation solution) to provide a lag period for the biomineralization process, allowing the biotreatment solution to be uniformly distributed within the soil and thereby improving the uniform distribution of calcium carbonate. The existing one-phase-low-pH method uses a low pH urease solution to prepare the biotreatment solution. However, long-term exposure to a low pH environment may result in a decrease in activity or even inactivation of urease, which is not conducive to the practical application of this technology. In this study, a modified one-phase-low-pH method using low pH cementation solution is proposed. Three sets of tests, including urease activity durability tests, solution tests, and sand column treatment tests, were conducted in this study to clarify the necessity and feasibility of the modified method. The test results showed that the acidic environment accelerated the decrease of urease activity over time. This phenomenon would be more pronounced at a lower pH, and urease would be immediately inactive at a pH lower than 4.5. Meanwhile, a high chemical concentration would also lead to a decrease in activity or even inactivation of urease. If urease is active and the initial pH of the biotreatment solution is higher than 4.5, the pH of the biotreatment solution will rapidly rise to a weakly alkaline state and enzyme-induced carbonate precipitation can occur. A biotreatment solution that would produce relatively uniform biomineralization can be prepared by using cementation solution with a pH range of 1.25–3.5 and bacterial urease solution in a volume ratio of 1:1. For the sand column with relatively uniform biomineralization, the pH of the cementation solution (or the initial pH of the biotreatment solution) has a negligible effect on the strength enhancement for similar calcium carbonate content.

Biomineralization has been used for the treatment of calcareous sand to improve its properties. Although many studies have been performed on the biomineralized calcareous sand under freshwater conditions, few studies were focused on the behaviors of calcareous sand in seawater. As the freshwater is scarce in island areas, the freshwater-based biomineralization technology may be unsuitable for the treatment. In this study, seawater-based bacterial enzyme induced carbonate precipitation (BEICP) was proposed to treat calcareous sand. A series of tests were conducted to verify the feasibility and efficiency of this treatment method through investigating the effects of seawater on the biomineralization and the properties of biomineralized calcareous sand in comparison with microbially induced carbonate precipitation (MICP). Test results reveal that seawater leads to the decrease of urease activity of bacterial cells and urease. NaCl, MgCl2, Na2SO4, and CaCl2 are the main inhibitory components in seawater, of which MgCl2 and CaCl2 have a strong influence on the urease activity of bacterial cells and urease, respectively. Compared to MICP treatment, BEICP-treated calcareous sand exhibits higher unconfined compressive strength and better biomineralization effects. The findings of this study can contribute to the application of biomineralization technology in island areas.

Soil contamination by heavy metals presents substantial ecological and geotechnical risks, thereby demanding sustainable remediation strategies. Conventional approaches, including chemical stabilization and microbial-induced carbonate precipitation (MICP), are limited by high costs, ecological disturbances, and sensitivity to environmental stressors. A plant-derived urease-driven enzyme-induced carbonate precipitation (EICP) system was evaluated for immobilizing cadmium (Cd2⁺), lead (Pb2⁺), and zinc (Zn2⁺) in contaminated soils. Systematic screening revealed that jack bean and watermelon seed ureases are optimal catalysts for heavy metal sequestration, achieving efficiencies of 87.3% for Cd2 ⁺ , 91.5% for Pb2 ⁺ , and 76.4% for Zn2 ⁺ . These high efficiencies are attributed to their catalytic specificity and the retained enzymatic activity under environmental stress. Critical process parameters were fine-tuned through iterative experimentation, maintaining a urea-CaCl₂ reaction stoichiometry of 1.5:1 molar ratio and calibrating the enzyme dosage to 1.2 U/g of soil matrix. This optimized operational range effectively promoted carbonate mineralization while preserving essential soil hydraulic properties, as evidenced by sustained permeability exceeding 10 ⁻ ⁵ cm/s throughout precipitation cycles. Durability assessments under simulated acid rain and freeze-thaw cycles demonstrated 82.5% retention of Cd2⁺ and 92.7% retention of unconfined compressive strength, outperforming conventional lime and MICP treatments. X-ray diffraction analysis confirmed the presence of stable crystalline phases. Field validation confirmed that the EICP protocol can be feasibly scaled to real-world sites with operational costs averaging $52 per cubic meter, representing a 61% reduction compared to microbial-based treatments. This plant-based EICP approach offers a scalable and cost-effective solution for ecological restoration and geotechnical stabilization in contaminated soils, demonstrating significant potential for sustainable environmental management.