2003 Volume 54 Issue 6 Pages 485-490
In order to examine the decolorization of dyeing effluent by enzyme, aqueous solutions of ten commercial anthraquinone dyes (C. I. Acid Blue 45, C. I. Acid Blue 25, C. I. Acid Blue 40, C. I. Acid Blue 41, C. I. Reactive Blue 19, C. I. Acid Green 27, C. I. Acid Green 25, C. I. Acid Blue 80, C. I. Reactive Blue 4, C. I. Reactive Blue 2) were treated with bilirubin oxidase (BO). Efficient decolorization of all ten dyes was confirmed by measuring the visible and UV absorption spectra of the dye solution to which the enzyme was added. An aqueous solution of purified C.I. Acid Blue 40, to which the enzyme was added, was shaken at 37°C. Aliquots of the solution after the specified time were analyzed by HPLC after removing the enzyme. The chromatograms showed that the decomposition of dye (C.I. Acid Blue 40) started immediately after the addition of the enzyme. A peak around a retention time of 5.2 min, which can be related to the decomposition intermediate, increased gradually after the addition of the enzyme and was reached after about 3 h. That peak was nearly maintained even after 24 h, although it gradually decreased. The absorption spectrum of the product at that peak was determined by a photodiode array analysis.