Metal and metalloid immobilization by microbiologically induced carbonates precipitation

The industrialization and growth of human population has increased the release and accumulation of metals and metalloids in the environment. Bioaccumulation and exposure to these elements have been associated with different types of diseases and cancer, thus looking for alternatives that decrease their bioavailability in the environment is crucial. Microbiologically induced carbonates precipitation (MICP) has been proposed as a potential bioremediation method to immobilize contaminating metals and metalloids. Studies published to date have mainly used ureolytic bacteria, reporting metal(loid)s removal percentages up to 100% for some toxic elements, thus demonstrating the effectiveness of this treatment. Various genera of bacteria, particularly Gram-positive, have been reported with MICP abilities. More recently, fungi have also been proposed as a viable alternative for the removal of these toxic elements by carbonate precipitation. This mini-review presents updated information about the main studies carried out to date using different types of microorganisms that perform MICP to decrease the environmental bioavailability of toxic metals and metalloids through the formation of metallic carbonates.