Decolorization of Reactive Brilliant Blue KN-R by immobilized cells of Rhodocyclus gelatinosus

Reactive Brilliant Blue KN-R is a typical kind of anthraquinone dye and in common use in textile, dyeing, and printing industries in China, which is difficult to degrade because of its conjugated structure. The decolorization of KN-R was investigated using Ca-alginate immobilized cells of Rhodocyclus gelatinosus XL-1 under anaerobic conditions. For KN-R decolorization by immobilized cells, the suitable pH is 5-8 and the suitable temperature is 25-40 degrees C. Immobilized cells could decolorize KN-R by co-metabolism in the presence of peptone, and the enhancement of peptone concentration was beneficial for anaerobic decolorization. Metal ions affected the metabolic activity of immobilized cells of R. gelatinosus XL-1. The activity of KN-R decolorization was appreciably increased by Mg2+ and Cr3+, but severely inhibited by Cu2+ and Ag+. The maximum absorption peak in visible spectrum shifted from 595 to 453 nm during ICN-R decolorization, indicating the formation of the intermediate product.