Biodecolorization of Acid Red GR by a newly isolated Dyella ginsengisoli LA-4 using response surface methodology

Decolorization of Acid Red GR by a newly isolated biphenyl-degrading bacterium, Dyella ginsengisoli LA-4 was presented in this paper. The optimal decolorization conditions were determined by response surface methodology (RSM) based on the rotatable central composite design. The results indicated that strain LA-4 possessed the highest decolorizing activity under anaerobic conditions with inoculation amount 6.49%, pH 7.06 and temperature 29 °C. Some ions such as Cu2+, Zn2+ could inhibit the decolorization, whereas 1 mmol/L of Mg2+, Ca2+, Co2+, Fe3+, Ni2+ and Mn2+ had no effects on the process. It was demonstrated that anthraquinone as a redox mediator could significantly accelerate the reduction process of azo dyes.