Decolorization and degradation of reactive orange 16 by Bacillus stratosphericus SCA1007

Efficient bacterial strain was isolated from the dye contaminated area and identified as Bacillus stratosphericus SCA1007 based on 16S rRNA gene sequence (GenBank under accession number KY992944). This isolate was selected based on its potential to efficiently decolorize reactive orange 16 dye which is extensively used in textile industries. Various culture conditions like dye concentration, temperature, pH, salinity, and additional nitrogen source were optimized in the present study. The optimal conditions for decolorization of reactive orange 16 was found to be: dye concentration 150 mg/L, pH 7, temperature 35 °C, and yeast extract as nitrogen source. The isolate was also resistant to 4% saline culture condition. Decolorization and degradation of dye were confirmed through UV-visible spectroscopy, Fourier transform infrared (FTIR) and liquid chromatography-mass spectrometry analysis (LC-MS). Toxicity studies were performed on Escherichia coli and Vigna radiata to confirm the non-toxic nature of the degraded metabolites. This is the first study demonstrating complete decolorization of reactive orange 16 dye by Bacillus stratosphericus SCA1007 at high salinity within 10 h of incubation under optimized conditions.