Microbial Biotransformation of Hexavalent Chromium [Cr(VI)] in Tannery Wastewater

Abstract

Tannery wastewater contains hexavalent chromium [Cr(VI)], which is one of the most prevalent contaminants due to its essential applications in tannery industries. Tannery wastewater also contains a complex of organic, inorganic, and dissolved solids which are more carcinogenic to human and aquatic life and result in adverse effects on the environment; hence treatment of these pollutants is a significant concern to the society. The removal of Cr(VI) by microorganisms predominantly occurs through biotransformation and adsorption, where the mechanism mainly depends on the surface nature of the biosorbent and the availability of the reductants. Hexavalent chromium removal using relevant methods such as biodegradation and microbial bioremediation, are carried out proficiently by the addition of indigenous or exogenous microbes. This elevates the degradation rate of Cr(VI) naturally to achieve remarkably higher removal effeciency in tannery wastewater and bring it to the permissible limits prior to discharge. This chapter mainly focuses on bioremediation and the mechanism of a microbial cell, sources, as well as its effects in a detailed manner for the emerging technologies in industrial applications.