A comprehensive review on biodegradation of azo dye mixtures, metabolite profiling with health implications and removal strategies
Bhavana Balachandran, Sabumon Pothanamkandathil Chacko
Abstract
Azo dye mixtures present in industrial effluents cause significant threats to both environmental integrity and human health. Biological treatment methods of azo dyes offer an affordable and nature-friendly solution; however, the metabolites resulting from biodegradation require further investigation. Different microbial groups including bacteria, yeast, and fungi, have shown promise in the degradation of azo dye mixtures, yet there remains a substantial gap in research concerning algal-based methods. The present work comprehensively highlights microorganisms that possess the ability to degrade azo dye mixtures. This review further serves to guide readers in the identification of azo dye metabolites and its potential health risks and toxic effects including responses within the human body. Finally, azo dye metabolites removal methods reported after biodegradation is summarized. Therefore, this review would ultimately encourage the adoption of microbial mediated azo dye degradation along with addressing future challenges and opportunities for research advancement in this field. Future investigations should prioritize (i) the recovery of valuable azo dye metabolites, such as aniline and its derivatives; to foster a circular economy, (ii) the mineralization of harmful metabolites generated during biodegradation and (iii) developing advanced computational methods to expedite the identification of effective biodegradation pathways and enhance process efficiency for the removal of azo dyes from industrial effluents.