Plant-based Enzyme-mediated Biodegradation of Azo dyes: A Review

Abstract

Azo dyes are a popular group of dyes in the printing, food, leather, cosmetic, textile, and pharmaceutical sectors and are the largest and most important group of colored chemicals due to their facile production procedure. It is characterized by the presence of an azo group (-N=N-). The stability of azo dyes makes it recalcitrant. Discharge of untreated waste water that contains colored compounds with azo dye reaches water streams and affects the organisms due to the toxicity of the dyes. Many physicochemical and chemical approaches have been used for the removal of dye from polluted water. Although these procedures effectively treat polluted water but become costly and may result in the formation of hazardous compounds. A microbial enzymatic decolorization is an environment-friendly approach that shows excellent removal efficiency at low operating costs however, it has certain downsides, such as a slow process rate and a longer assimilation phase. Alternatively, enzymes derived from various sources can be employed to biodegrade and decolorize azo dyes. For the treatment of dye-based chemicals, enzymes extracted from plants have benefits over other approaches. They are believed to have a significant potential to degrade the recalcitrant pollutants present in the effluent from industries i.e., laccases, polyphenol oxidases, azoreductases, and different peroxidases like manganese peroxidase, lignin peroxidases, and decolorizing peroxidases, are the common enzymes that are isolated from plants and have the potential in the biodegradation of colored compounds. The importance of these enzymes in the treatment of industrial wastewater is unquestionable.