Urease-catalyzed microbial and enzymatic carbonate precipitation for eco-friendly heavy metal remediation.

Abstract

Heavy metal contamination significantly threatens environmental and public health, necessitating effective and sustainable remediation technologies. This review explores two innovative bioremediation techniques: microbially induced calcium carbonate precipitation (MICP) and enzyme-induced calcium carbonate precipitation (EICP). Both techniques show promise for immobilizing heavy metals in laboratory and field settings. MICP utilizes the metabolic activity of ureolytic microorganisms to precipitate calcium carbonate, sequestering heavy metals such as lead, cadmium, and arsenic as stable metal-carbonate complexes. EICP, on the other hand, employs urease enzymes to catalyze calcium carbonate precipitation, offering greater control over reaction conditions and higher efficiency in environments unfavorable to microbial activity. This mini-review compares the mechanisms of MICP and EICP, focusing on factors influencing their performance, including enzyme or microbial activity, pH, temperature, and nutrient availability. Case studies illustrate their success in sequestering heavy metals, emphasizing their practical applications and environmental benefits. A comparative analysis highlights the strengths and limitations of MICP and EICP regarding cost, scalability, and challenges. This review synthesizes research to support the advancement of MICP and EICP as sustainable solutions for mitigating heavy metal contamination.