Biodegradation of reactive textile dye Red BLI by an isolated bacterium Pseudomonas sp. SUK1 D.C. Kalyani, P.S. Patil, J.P. Jadhav, S.P. Govindwar * Department of Biochemistry, Shivaji University, Kolhapur 416 004, India Received 2 November 2006; received in revised form 30 April 2007; accepted 30 June 2007 Available online 31 August 2007 Abstract A novel bacterial strain capable of decolorizing reactive textile dye Red BLI is isolated from the soil sample collected from contam- inated sites of textile industry from Solapur, India. The bacterial isolate was identified as Pseudomonas sp. SUK1 on the basis of 16S rDNA analysis. The Pseudomonas sp. SUK1 decolorized Red BLI (50 mg l 1 ) 99.28% within 1 h under static anoxic condition at pH range from 6.5 to 7.0 and 30 °C. This strain has ability to decolorize various reactive textile dyes. UV–Vis spectroscopy, FTIR and TLC analysis of samples before and after dye decolorization in culture medium confirmed decolorization of Red BLI. A significant increase in the activities of aminopyrine N-demethylase and NADH-DCIP reductase in cells obtained after decolorization indicates involvement of these enzymes in the decolorization process. Phytotoxicity testing with the seeds of Sorghum vulgare and Phaseolus mungo, showed more sensitivity towards the dye, while the products obtained after dye decolorization does not have any inhibitory effects. Ó 2007 Elsevier Ltd. All rights reserved. Keywords: Isolation; Red BLI; Dye decolorization; Reactive textile dyes; Phytotoxicity 1. Introduction Rapid industrialization and urbanization resulted in the discharge of large amount of waste to the environment, which in turn creates more pollution. Majority of the col- ored effluents consisting of dyes, released to the environ- ment from textile dyestuff and dyeing industries. Color pollution in the environment is escalating problem (Coo- per, 1995). Such pollution is particularly associated with the reactive dyes, which accounts for a significant propor- tion of the total dye market. Due to the relatively low levels of dye fiber fixation, in current reactive dyeing processes, up to 50% of the dye that present in the original dye bath is lost to the wastewater (Bumpus, 1995). These highly sta- ble reactive dyes, which are not degraded by the conven- tional wastewater treatment processes, enter in to environment in the form of colored wastewater (Stolz, 2001). Azo dyes represent a major group of dyes mostly used in industry (Chen et al., 2004; Kumar et al., 2006; Jad- hav et al., 2007), which are causing environmental concern because of their color, biorecalcitrance and potential toxic- ity to animals and human (Levine, 1991; Hildenbrand et al., 1999; Martins et al., 2002). It is very difficult to treat the effluents from the textile and dyeing industries by com- monly used physical and chemical methods mainly because of its high BOD, COD, heat, color, pH and the presence of metal ions. Several physicochemical decolorization tech- niques have been reported, few of them were accepted by the textile industries (Okazaki et al., 2002; Da Silva and Faria, 2003). The physical and chemical methods have disadvantages of being highly expensive, coupled with the formation of large amount of sludge and the emission of toxic substances (Johnson et al., 1978). In addition, the accumulation of concentrated sludge creates a disposal problem (Banat et al., 1996). The general approach of bioremediation is to improve the natural degradation 0960-8524/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.biortech.2007.06.058 * Corresponding author. Tel.: +91 231 2609152; fax: +91 231 2691533. E-mail address: spg_biochem@unishivaji.ac.in (S.P. Govindwar). Available online at www.sciencedirect.com Bioresource Technology 99 (2008) 4635–4641