Advances in bioremediation of hexavalent chromium: cytotoxicity, genotoxicity, and microbial alleviation strategies for environmental safety

Abstract Chromium (Cr) is a potentially toxic metal originating from natural processes and anthropogenic activities. This heavy metal is highly toxic, carcinogenic to living organisms, and has an ecological risk. Therefore the evaluation and remediation of contamination by Cr has attracted extensive investigations. Cr(VI)-resistant microorganisms provide important tools with great biological relevance and biotechnological applications. This chapter summarizes the bioremediation technologies of Cr(VI) oriented to theoretical and practical applications, and provides a comparative study of different removal mechanisms (biosorption, bioaccumulation, complexation, and reduction of Cr (VI) to Cr (III)). The most relevant results of several investigations focused on the different microorganisms and culture strategies were also discussed. However, bioremediation is still a challenging technique and new strategies to alleviate this metallic pollutant from the environment are still being investigated.