Isolation and Screening of Dye Degrading Micro-organisms from the Effluents of Dye and Textile Industries at Surat

Abstract

Text ile dyes have been used since the Bronze Age. They also constitute a prototype 21 st -century speciality chemicals market. Effluent and soil samp les were collected fro m textile industry at Surat. The pH, temperature, BOD, COD, Nitrate and Nitrite values were co mpared with the values given by the Bureau of Indian Standards. The culture med iu m was designed and standardized in the laboratory for the isolation and degradation of the dyes. Pure cultures were screened on the basis of colony morphology. Three different types of unique cultures were selected and named as isolates S1, S2 & S3. Out of 12 dyes used, isolate S1 showed degradation on the maximu m nu mber of dyes (five) in co mparison to other isolates (isolates S2 and S3). Thus, isolate S1 was used for the further studies. The isolate S1 was used for the study of the amount of dye to be degraded. For this study Red BB dye was chosen. Because, isolate S1 showed maximu m degradation on Red BB dye within less time of incubation in comparison with other dyes. Almost all isolates showed the positive results in some of the biochemical tests. Thus most of the isolates can have the capacity to produce the enzyme tryptophanase, indole production, citrate permease (citrate as carbon and energy source), catalase enzy me, degradation of glucose oxidatively as well as fermentatively, urease, gelatinase, production of acid and gas (allo w to ferment lactose and/or sucrose) and fermentation of sugar, lactose, sucrose, mannitol and glucose. Total cellu lar fatty acids profiling has been considered to be one of the important and ideal tool for identification of microorganis ms. On the basis of fatty acid pro filing of isolate S1 the similarity index indicated as Bacillus cereus GC subgroup A (similarity index 0.825), B. thuringiensis sub sp. israelensis (similarity index 0.552) and for B. thuringiensis sub sp. Kurstakii (similarity index 0.511). The isolate S1 was assumed to be B. cereus GC subgroup A. Thus this isolates can be used to degrade harmful azo dyes utilized by the dye, text ile, paper, in k industries etc.