FTIR Spectroscopy Applied in Remazol Blue Dye Oxidation by Laccases

Abstract

We have used FTIR \\ith attenuated total reflectance (ATR) technique to analyze the decolourization process ofRemazol Blue dve (RB19) caused by the oxidative activity of laccase enzyme. lt is known that laccases catalyze the oxidation of a large range of phenolic compounds and aromatic amines carrying out one-electron oxidations, although also radicals could he fonned which undergo subsequent nonenzvmatic reactions. TI1e enzyme laccase is a copper-containing polyphenol oxidase (EC 1.10.3.2) which has been tested as a potential altemative in detoxification of environmental pollutants such as dves present in wastewaters generated for the textile industry . In order to ensure degradation or avoid fonnation of toxic compounds it is important to establish the mechanism by which laccase oxidizes dyes. In this research individual ATR-Fl'IR spectra have been recorded for several reaction limes bctWC<-11 0 to 236 hours, and the temporal dq.Jendence of the reaction was anal yzed through ti1e relative diminution of ti1e intensity of ti1e infrared band at 1127 cm•1 (associated to C-N vibration), '' til respect to ti1e intensity of the band at 1104 cm•1 (associated to S=O) from sulphoxide group. Decolourizalion process of this dye hy laccase could be attributed to its accessibility on tile secondary amino group, which is a potential point of attack of laccases, abstracting the hvdrogen atom. Ths decolourization process of remazol blue dye by laccase enzyme might in a future replace ti1e traditionally high chemical, energy and water consurning textile operations.