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

Textile dyes have been used since the Bronze Age. They also constitute a prototype 21st-century speciality chemicals market. Effluent and soil samples were collected from textile industry at Surat. The pH, temperature, BOD, COD, Nitrate and Nitrite values were compared with the values given by the Bureau of Indian Standards. The culture medium 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 maximum number of dyes (five) in comparison 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 maximum 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 enzyme, degradation of glucose oxidatively as well as fermentatively, urease, gelatinase, production of acid and gas (allow to ferment lactose and/or sucrose) and fermentation of sugar, lactose, sucrose, mannitol and glucose. Total cellular fatty acids profiling has been considered to be one of the important and ideal tool for identification of microorganisms. On the basis of fatty acid profiling 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, textile, paper, ink industries etc.