Bio-degradation of Azo Dye Acid Orange-10 by a New Isolate of Bacillus subtilis Isolated from Soil Sample around Textile Industry in South Karnataka

Abstract

Untreated effluents from the textile industry affect aquatic life irreversibly. Synthetic dyes not only change the color of water resources but also make them hazardous.The main objective of the study was to evaluate the decolorizing potential of a new isolate of Bacillus subtilis from soil samples contaminated with industrial effluent in and around textile industrial area in South Karnataka. This isolate of Bacillus subtilis has high decolorizing potential and took only 24 hrs for complete decolorization of acid orange-10 azo dye at 200ppm. Different parameters like temperature, pH, aeration, dye concentration and inoculum size were optimized for complete decolorization of Acid orange-10 azo dye by this isolate of Bacillus subtilis. The dye was completely decolorized at 400C within 24 hrs and it was capable of decolorizing 700 ppm dye in 72 hrs. Optimum pH was found to be 8.5 and maximum decolorization was achieved under static conditions. As the inoculum size increased, the time taken for complete decolorization of Acid orange-10 dye was decreased from 36 hrs at 1% to 16 hrs at 10% of inoculum size. The new isolate decolorizes 100 ppm of dye completely (i.e.100%) within 12hrs of incubation. The time taken for the complete decolorization increased with increase in the concentration of Acid orange-10 azo dye. In conclusion, the new isolate of Bacillus subtilis from soil samples contaminated with textile industrial effluent was found to be a potential candidate for decolorization of Acid orange-10 azo dye in textile effluents.