Enzymatic Degradation of Azo Dyes -A Review

Abstract

Synthetic organic colourants (e.g., azo dyes) are used commonly in different industries ranging from food, textile production, printing and pharmaceuticals. The majority of these dyes are recalcitrant, so that they can impart colour on various raw materials. Certain dyes, dye precursors and some aromatic amine metabolites produced through biotransformation of dye compounds have been shown to be carcinogenic. The release of dyes into the environment constitutes a small proportion of water pollution, and the coloured wastewaters represent a serious environmental problem and a public health concern. Colour removal, especially from textile wastewaters, has been a big challenge over the last few decades; until now there is no single and economically attractive treatment that can effectively decolourize textile mill effluent. This review narrates the different enzymatic mechanisms in the reduction of azo dyes.