Biodecolourization and biotransformation of textile dyes remazol violet-5R and remazol brillant orange-3R by Bacillus sp. DT9 isolated from textile effluents

The present study aims to evaluate RV-5R and RBO-3R decolourizing potential of Bacillus sp. DT9 isolated from textile effluent in Denizli (Turkey). In present study, maximum dye-decolourizing efficiency of the culture was achieved at 25 mg l-1 concentration of RV-5R and 500 mg l-1 concentration of RBO-3R. While the optimum dye-decolorizing activity of DT9 was observed at pH 7.5 and 37oC in sucrose for RV-5R (91.66% decolourization rate), 500 mg l-1 RBO-3R concentration by Bacillus sp. DT9 was decolourized at pH 9.0 and 30°C in sucrose/peptone containing medium (98.41% decolourization rate). In other step of study, DT9 was immobilized in Ca-alginate. According to immobilization results, the percentage of decolourization of RV-5R was found very similar to cell free result. But, the percentage of decolourization of RBO-3R decreased 30.0%, when DT-9 cells were immobilized in Ca-alginate. Metabolites of the RV-5R and RBO-3R biodegradation were analysed via ESI-TOF/MS analysis at the end of decolourization process, and the biotransformation and dimerization was confirmed.