Study on the influence of iron redox cycling microorganisms on heavy metals in the environment

Iron redox cycling microorganisms include Fe(Ⅱ)-oxidizing bacteria and Fe(Ⅲ)-reducing bacteria. The oxidation (or reduction) of Fe2+(or Fe3+) mediated by these microorganisms is usually accompanied by the migration and transformation of a series of heavy metal elements, which plays an important role in influencing the bioavailability and mobility of heavy metals in the environment. This paper reviewed the iron redox cycling microorganisms in the environment, and discussed the mechanism of iron redox cycling microorganisms driving heavy metal migration and transformation from the following aspects:immobilization of heavy metals by iron minerals produced by iron oxidizing bacteria; reduction and dissolution of iron minerals and formation of secondary minerals mediate by iron-reducing bacteria; and microbial metabolism of iron redox cycling microorganisms coupled with heavy metal speciation transformation. Furthermore, the remediation potential of iron redox cycling microorganisms on heavy metals such as arsenic, cadmium, chromium, copper and lead in the environment were summarized through research examples. Future research can focus on the biomineralization mechanism of specific microorganisms, regulation of heavy metal remediation by biomineralization, and the application of iron redox cycling microorganisms in remediation of heavy metal contaminated sites. This paper aims to provide theoretical and application basis for remediation of heavy metal pollution based on iron redox cycling microorganisms.