Bacterial biomineralization of heavy metals and its influencing factors for metal bioremediation

Increasing industrial pollution and certain hazardous agricultural practices have led to the discharge of heavy toxic metals into the environment. Among different bioremediation techniques, biomineralization is the synthesis of biomineral crystals extracellularly or intracellularly. Several bacteria, such as Bacillus cereus, Pseudomonas stutzeri, Bacillus subtilis, and Lactobacillus sphaericus have been found to induce heavy metal precipitation and mineralization for bioremediation. This article summarizes the different biomineralization mechanisms of bacterial-induced heavy metal biomineralization, mainly microbial-induced carbonate precipitation (MICP), microbial-induced phosphate precipitation (MIPP), and microbial-induced sulphide precipitation (MISP). Moreover, bacterial structures such as cell wall, biofilm, and extracellular polymeric substances (EPS) influence mineralization and control bacterial compartmentalization of heavy metal precipitation. Several genes control the efficiency of biomineralization in bacteria, such as ureA, ureB, ureC, phoA, dsrA, dsrB, dsrC, dsrD, dsrE, luxS, and ompR. This biomineralization mechanism provides new and broad prospects for its application in soil improvement, industrial applications, and wastewater treatments. In addition, bacterial genetic modification holds immense potential for advancing the biomineralization process to meet diverse environmental and industrial needs.