Azo dye bioremediation: An interdisciplinary path to sustainable fashion

Abstract

Textile effluents constitute a significant source of environmental contamination due to the substantial discharge of recalcitrant azo dyes. These synthetic xenobiotic compounds, extensively employed across various industries, represent a predominant class of colorants. The persistence of azo dyes in aquatic ecosystems poses a formidable threat to biota, encompassing flora, fauna, and anthropogenic populations. These recalcitrant pollutants can infiltrate agricultural systems through irrigation practices, facilitating their entry into trophic networks and eliciting deleterious effects on human health. Conventional physico-chemical treatment methodologies have been implemented for the remediation of dye-laden wastewater; however, the inherent stability and color-fastness of azo dyes render the decolorization process arduous. Stringent environmental regulations have been promulgated to mitigate the discharge of these hazardous compounds into aquatic systems. Bioremediation emerges as a promising solution for the effective treatment of toxic synthetic dyes. This review elucidates biological decolorization technologies for azo dyes exhibiting carcinogenic, mutagenic, and phytotoxic properties. It explores microbial biodecolorization mechanisms, emphasizing the roles of bacteria, fungi, and algae, and their enzymes in the adsorption and degradation of dye molecules, facilitating their complete mineralization into innocuous entities. Strategies to enhance biodecolorization efficiencies, such as sequential aerobic-anaerobic decolorization and immobilization techniques, are also discussed. Immobilization of biological decolorizers enables their long-term efficient utilization. Various technologically advanced interdisciplinary approaches to mitigate azo dye problems have also been covered. This comprehensive review aims to guide researchers and environmentalists in devising effective treatment modalities for toxic dye remediation and environmental conservation.