The textile industry is a rapidly developing industrial sector that produces – wastewater laden with various pollutants including synthetic dyes and heavy metals. Remazol Black-B (RB-B) is a group of azo dyes that are extensively used in textile industries. The objective of this study was to evaluate the potential of the Streptomyces hygroscopicus PTCC1132 to remove RB-B and to determine optimal conditions for decolorizing. The Taguchi optimization approach was used to reduce the number of experiments and the time needed to find optimum conditions. The effect of operating parameters such as temperature, pH, initial RB-B concentrations, and salt dosage were evaluated by defined factor 4 on four-level Taguchi L16 orthogonal array. Qualitek-4 software was used for data analysis. Maximum efficiency for RB-B decol- orization was obtained at 33°C; wherein the solution pH was set to 9.0; and RB-B concentration and salt concentration were 5,000 mg/L and 1%, respectively. The corresponding decolorization efficiency was obtained as 95.27% at under optimized conditions confirming that the bacteria exhibits resistance against the toxic effects of RB-B, especially at high dye concentrations. Our findings indicate of the effectiveness of the evaluated microorganisms for the removal of RB-B from dye-containing effluents.