Decolorisation of reactive dye wastewater and the effect of surfactants using laccase

Laccase (benzenediol, oxidoreducase; Enzyme Commission Number) is a multi-copper oxidase from biomass. Laccase enzyme recycling on molecular oxygen as an electron acceptor can be applied for the decolorisation of synthetic dyes. The decolorisation of 49 commercial reactive dyes using laccase was investigated. The effects of diverse structure surfactants on decolorisation are discussed. The absorption spectra of reactive dyes after a laccase biodegradable reaction were analysed. Reactive dyes based on anthraquinone and azo structures could be decolorised using the enzyme and their chemical structures broken. Reactive dyes based on an anthraquinone structure were easier to decolorise than those based on an azo structure. Surfactants could affect the decolorisation of dyes with an enzyme. The effect of nonionic surfactant on the decolorisation of anthraquinone dyes was the reverse. The cationic surfactant could improve the decolorisation rate of diazo dye. The effect of the anionic surfactant on dye decolorisation was small. Most commercial reactive dyes could be decolorised and biodegraded using a laccase enzyme under mild conditions. Laccase enzyme biotechnology has potential applications in the decolorisation of reactive dye wastewater.