Study on the Decolorization and Degradation of Reactive Dyes Used in the Textile Industries of Tamil Nadu, India

Textile dyes are one of the most prevalent type of chemicals in use today. Around 10,000 different dyes with an annual production of more than 7x10(5) metric tons worldwide are commercially available. Two percent of dyes that are produced are discharged directly in aqueous effluent and 10% are subsequently lost during the textile coloration process. Some of the azo dyes, xanthene dyes and anthroquinone dyes are known to be very toxic and mutagenic to living organisms. With the increasing use of a wide variety of dyes, pollution by dye-waste water is becoming increasingly alarming. The two major sources of release of dyes into the environment are the textile and dye stuff manufacturing industries. The present study was carried out in an attempt to decolorize seven commonly used textile dyes such as Reactive Back HFGR, Reactive Red, Reactive Yellow I, Reactive Yellow II, Reactive Blue and Reactive Black and Colonial Red. Soil sample from the sludge waste was taken for the isolation of microorganisms and 24 bacteria were isolated. All these were screened for the ability to decolorize all seven dyes and were found to be encouraging. Experiments were carried out to understand the role of Sources of Carbon, Nitrogen and their composition on the decolorizing ability and their synergistic relationship/role of the bacterial species in decolorization process. Results reveal the existence of wide variety of organisms capable of decolorizing a wide range of dyes and it is worth investigating further into the molecular details of the phenomenon.