A strain of Pseudomonas aeruginosa (Pseudomonas sp. R1), which can efficiently decolorize reactive red X-3B, was isolated from activated sludge in a dye plant, and the decolorizing mechanism was explored in this paper. The result shows that Pseudomonas sp. R1 has very good capability for decolorization of reactive red X-3B and the decolorization rate is increased by 9.1% after optimization of the experimental parameters, which means that 89.6% of the reactive red can be removed. Investigation on decolorization mechanism showed that the decolorizing capability of Pseudomonassp. R1 was significantly affected after plasmids in Pseudomonassp. R1 were eliminated by acridine orange (AO). Meanwhile, E. coli DH5a could gain decolorizing capability after transformed with the plasmids. Plasmid elimination and transformation tests proved that the decolorizing gene in Pseudomonas sp. R1 exists in the plasmid.
Keywords: Dye wastewater; Pseudomonas; azo-dye; bacteria decolorization; decolorization mechanism; plasmid.