Biologia 70/1: 11—18, 2015 Section Cellular and Molecular Biology DOI: 10.1515/biolog-2015-0008 Evaluation of the efficiency of isolated bacterial consortium PMB11 in removal of colour, degradation and reduction of toxicity from textile dye effluent* Pratibha Patil 1 **, Vidya Patil 2 , Swati Surwase 1 & Jyoti Jadhav 1 1 Department of Biotechnology, Shivaji University, Kolhapur – 416 004, Maharashtra, India; e-mail: patilpratibha.3579@gmail.com 2 Department of Microbiology and Biochemistry, Yashavantrao Chavan Institute of Science, Satara – 415001, Maharashtra, India Abstract: The aim of the present study was to investigate the textile effluent degrading potential of an isolated bacterial consortium PMB11. The consortium had the capacity to decolourize various textile dyes and textile effluent. Ninety- one percent textile effluent decolourization was observed within 120 hours. The physiochemical characterization of textile effluent indicates reduction in the total hardness (CaCO3), fluorides, chlorides, sulphate, chemical oxygen demand, and biochemical oxygen demand of textile effluent after treatment with consortium PMB11. Induction in the activities of NADH- dichlorophenolindophenol reductase, azoreductase, and aminopyrine N-demethylase was observed after decolourization, which indicates involvement of these enzymes in the decolourization and degradation process. The biodegradation of dyes from effluent was confirmed using various analytical techniques, such as UV-Vis spectroscopy, Fourier transform infrared spectroscopy, gas chromatography – mass spectroscopy, and HPLC. A phytotoxicity study was performed to confirm the less toxic nature of the degradation metabolites than the effluent. Key words: textile effluent; decolourization; biodegradation; azoreductase; phytotoxicity. Abbreviations: BOD, biochemical oxygen demand; COD, chemical oxygen demand; DCIP, dichlorophenolindophenol; FTIR, Fourier transform infrared spectroscopy; GC-MS, gas chromatography – mass spectroscopy, NADH, nicotinamide adenine dinucleotide reduced disodium salt; TDS, total dissolved solids; TSS, total suspended solids. Introduction The world’s ever-increasing population and its progres- sive adoption of an industrial-based lifestyle have led to an obvious increased anthropogenic impact on the biosphere. During textile production, hazardous com- pounds are released at the various stages of operation in an effort to improve human standards of living and fashion. Their unplanned infringement into the environ- ment is a great paradox, and it can reverse the stan- dards of living by negative impact on the environment (Asamudo et al. 2005). About 3,000 azo dyes are used in various indus- tries, such as paper, food, cosmetics, and pharmaceuti- cals (Pan et al. 2012). Over 7 × 10 5 metric tons are pro- duced annually worldwide (Ali 2010). The textile indus- try has led to increased volumes of textile wastewater, which causes environmental problems. Textile wastewa- ter is a complex mixture of several polluting substances, including heavy metals, bleaching agents, fibres, and various types of dyes and dyestuffs (Correia et al. 1994). It can percolate and pollute underground water; pollu- tants cannot be restricted within specific boundaries where they are discharged (Asamudo et al. 2005). This alters the pH, increases the biochemical oxygen demand (BOD) and chemical oxygen demand (COD), and gives rivers intense colourations (Olukanni et al. 2006). Dyes of different structures are often used in the textile processing industry, and therefore, the effluents from the industry are markedly variable in composi- tion (Kalyani et al. 2009). The difficulties encountered in wastewater treatment resulting from dyeing opera- tions lie in the wide variability of the dyes used and in the excessive colour of the effluents (Machado et al. 2006). The characteristic structure of dye, and par- ticularly reactive dye, is very complex and difficult to degrade or eliminate (Cronk & Fennessey 2001) from textile wastewater. Reactive dye can dissolve in water as it is a highly soluble compound, and the resultant change in the water colour is unattractive to the pub- * Based on a contribution presented at the International Conference on Advances in Biotechnology & Bioinformatics (ICABB-2013), November 25–27, 2013, Pune, Maharashtra, India ** Corresponding author c 2015 Institute of Molecular Biology, Slovak Academy of Sciences Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 7/6/15 2:38 AM