ORIGINAL PAPER Biodegradation of C.I. Reactive Red 195 by Enterococcus faecalis strain YZ66 Madhuri Sahasrabudhe Mate • Girish Pathade Received: 6 May 2011 / Accepted: 22 August 2011 / Published online: 6 September 2011 Ó Springer Science+Business Media B.V. 2011 Abstract Synthetic dyes are extensively used in textile dyeing, paper, printing, colour photography, pharmaceu- tics, cosmetics and other industries. Among these, azodyes represents the largest and most versatile class of synthetic dyes. As high as 50% of the dyes are released into the environment during manufacture and usage. Traditional methods of treatment are found to be expensive and have operational problems. Biological decolourization has been investigated as a method to transform, degrade or miner- alize azo dyes. In the present studies bacteria from soil from dye waste area, dye waste, sewage and dung were subjected to acclimatization with C.I. Reactive Red 195 an azo dye, in the basal nutrient media. The most promising bacterial isolate was used for further dye degradation studies. The 16s rRNA gene sequencing and biochemical characteristics revealed the isolated organism as Entero- coccus faecalis strain YZ66. The strain showed 99.5% decolourization of the selected dye (Reactive Red 195–50 mg/l) within one and half hour in static anoxic condition. The optimum pH and temperature for the dec- olourization was 5.0 and 40°C respectively. The biodeg- radation was monitored by UV–Vis, FTIR, TLC and HPLC. The final products were characterized by Gas chromatography and Mass Spectrophotometry. Toxicity study demonstrated no toxicity of the biodegradation product. The results suggest that the isolated organism E. faecalis strain YZ 66 can be used as a useful tool to treat waste water containing reactive dyes. Keywords Azo dye  RR195  Enterococcus faecalis  Biodegradation  ABTS  SM  LP Introduction Azo dyes constitute the largest and most versatile class of dyes used for textile dyeing and other industrial applica- tions (Syed et al. 2009; Bafana et al. 2008; Pandey et al. 2007; Pourbabae et al. 2005; Wesenberg et al. 2003; Stolz 2001). Azo dyes are xenobiotics compounds characterized by the presence of one or more azo linkages (N=N) and aromatic rings (Mohana et al. 2008; Moutaouakkil et al. 2003). They consist of a diazotized amine coupled to an amine or a phenol. They are the largest class of dyes with the greatest variety of colours. At least 3,000 different varieties of azo dyes are extensively used in textile, paper, food, cosmetics and pharmaceutical industries (Jirasri- pongpun et al. 2007; Kalme et al. 2007; Chang et al. 2001; Rodriguez et al. 1999). Amongst various applications of synthetic dyes about 300,000 tons of different dyestuffs are used per year for textile dyeing operation (Keharia et al. 2004). Among these dyes, azo dyes are the most widely used and accounts for over 60% of the total number of dyes known to be manufactured (Fu and Viraraghavan 2001). In all 100,000 commercial available dyes exist with over 7 9 10 5 metric tones of dyestuff produced annually (Hempriya et al. 2010; Dawkar et al. 2009; Parshetti et al. 2009; Joshi et al. 2008). Amongst the azo dyes, reactive dyes the only textile colourants designed to bind covalently with cellulosic fibers and are extensively used in textile industry on account of the variety of colour shades, high M. S. Mate (&) Department of Microbiology, Maulana Azad College, Aurangabad, Maharashtra, India e-mail: sahasrabudhemadhuri@gmail.com G. Pathade Department of Biotechnology, Fergusson College, Pune, Maharashtra, India e-mail: girishpathade@yahoo.co.in 123 World J Microbiol Biotechnol (2012) 28:815–826 DOI 10.1007/s11274-011-0874-4