Biodegradation of Azo Dye Disperse Orange S-RL by a Newly Isolated Strain Acinetobacter sp SRL8

The strain SRL8, which could decolorize the azo dye disperse orange S-RL (S-RL), was first isolated from sludge and identified as Acinetobacter sp. through physiobiochemical identification and 16S rRNA gene sequences. The effects of temperature, pH, dye concentration, O-2, and glucose concentration on S-RL decolorization by the strain SRL8 were studied. The optimal conditions were 30 degrees C, pH 7.0, 4g.L-1 of inoculation (wet cells), and microaerophilic incubation. The decolorization percentage for S-RL by the strain SRL8 could reach 90.2% under optimal conditions. The strain SRL8 was highly tolerant to the azo dye SRL up to 300 mg.L-1 and it had a broad decolorizing spectrum. According to the Monod equation, kinetic parameters of decolorization by SRL8 were calculated. The v(max) and Km were 5.57 x 10(-3) h(-1) and 14.53 mg.L-1, respectively.