Abstract

Using the BMM medium containing 100 mg/L of reactive brilliant red X-3B, a decolorizing bacterium with higher decolorization activity was isolated and it showed a decolorization zone of 10 mm; this decolorizing bacterium was identified as Pseudomonas putida WLY based on physiological and biochemical characteristics as well as 16srRNA sequence. In this study, the effects of P. putidaWLY’s decolorizing ability, for example, glucose concentration, temperature, O₂, pH and dye concentration, were investigated. The results show that under 40°C, pH 7.0, glucose concentration 0.2%, O₂  absence and concentration of X-3B of 30 mg/L, the decolorization rate in 24 and 48 h was 86.3 and 93.2%, respectively. The azoreductase produced by P. putida WLY was extracellular and induced according to electrophoresis experiments and decolorization tests. After purification by ion exchange and gel chromatography, its molecular weight was estimated to be 28,000 Da by SDS-PAGE.

Key words: Pseudomonas putida; reactive brilliant red X-3B, biodecolorization, azoreductase.