L Moharrery - Department of Chemical engineering, Islamic Azad university, Robat Karim Branch, Tehran, Iran
M Otadi - Department of Chemical engineering, Islamic Azad university, Tehran Central Branch, Tehran, Iran
R Amiri - Department of chemistry, Islamic Azad university, Tehran Central Branch, Tehran, Iran
M.M Rezaei Zangeneh - Department of Chemical engineering, Islamic Azad university, Tehran Central Branch,Tehran, Iran

Decolorization ability of Toluidine Red (TR), an oil soluble azo dye by Halomonas strain D2 was optimized under different environmental conditions using one factor at a time (OFAT) method. The best decolorization was achieved at 25ppm dye concentration, pH 6.5, temperature 35°C and 5% (w/v) NaCl. UV-Vis and HPLC analysis suggested that decolorization was occurred under biodegradation mechanism rather than biosorption. Identification of degradation products was done with GC/MS analysis. Final compounds appeared at m/z 193 and m/z 77 corresponding to 2-(2-carboxy vinyl) benzoic acid and Benzene respectively. The pathway for biodegradation mechanism was proposed. According to the findings, Halomonas strain D2, was a suitable strain for treatment of waste waters which are contained of salts, oil base colors and heavy metals.

Decolorization, Degradation, Halomonas strain D2, Toluidine Red