Review Fungal decolouration and degradation of azo dyes: A review Sudip Kumar SEN a , Smita RAUT b , Partha BANDYOPADHYAY a , Sangeeta RAUT b, * a Ingene Research Laboratory, Biostadt India Limited, Aurangabad, Maharashtra, India b Department of Biotechnology, Gandhi Institute of Engineering and Technology, Gunupur, Odisha, India article info Article history: Received 8 April 2016 Received in revised form 10 June 2016 Accepted 12 June 2016 Keywords: Azo dyes Bio-sorption Decolouration Degradation Fungi Toxicity abstract The textile industry is a substantial consumer of water and produces enormous volumes of contaminated water; the most important contaminants are azo dyes. Fungal processes for the treatment of textile wastewater have the advantage of being cost-effective and envi- ronmentally friendly and producing less sludge. Unlike bacteria, fungi possessed strong ability of degrading complex organic compounds by producing extracellular ligninolytic en- zymes including laccase, manganese peroxidase and lignin peroxidase, hence, researchers paid more attention on fungi in recent years. The mechanism of fungal decolouration oc- curs from adsorption, enzymatic degradation or a combination of both. The goal of fungal treatment is to decolorize and detoxify the dye contaminated effluents. In this review, we summarize the methodologies used to evaluate the toxicity of azo dyes and their degrada- tion products. Recent studies on the decolouration or degradation of azo dyes with Advanced Oxidation Processes (AOPs) and Microbial Fuel Cells (MFCs) are discussed in this review. ª 2016 British Mycological Society. Published by Elsevier Ltd. All rights reserved. 1. Introduction In recent years, greater attention has been paid to the discharge of effluents containing synthetic dyes (Miranda et al., 2013). Worldwide, 280,000 tons of textile dyes are dis- charged in industrial effluents every year (Jin et al., 2007). To dye 1 kg of cotton with reactive dyes, 0.6e0.8 kg NaCl, 30e60 g dyestuff and 70e150 L water are necessary; the wastewater produced has 20e30 % of the applied unfixed reactive dyes, with an average concentration of 2000 ppm, high salt content and dyeing auxiliaries (Babu et al., 2007). The release of these effluents into the environment is unde- sirable due to the serious environmental problems linked with the dyes and their breakdown products (Ozdemir et al., 2013). Among commercial synthetic dyes, azo dyes are the largest class with a broad range of colours and struc- tures and represents up to 70 % of the total textile dyestuffs used (Lang et al., 2013). Azo dyes are regularly used in various applications in food, pharmaceutical, paper, cosmetic, textile and leather industries (Saratale et al., 2013). These dyes belong to the class of aromatic and heterocyclic compounds having the azo bond (eN]Ne) which are recalcitrant and * Corresponding author. Department of Biotechnology, Gunupur, Rayagada, Odisha, 765022, India. E-mail address: research.sangeeta@gmail.com (S. Raut). journal homepage: www.elsevier.com/locate/fbr fungal biology reviews xxx (2016) 1 e22 http://dx.doi.org/10.1016/j.fbr.2016.06.003 1749-4613/ª 2016 British Mycological Society. Published by Elsevier Ltd. All rights reserved. Please cite this article in press as: Sen, S.K., et al., Fungal decolouration and degradation of azo dyes: A review, Fungal Biology Reviews (2016), http://dx.doi.org/10.1016/j.fbr.2016.06.003