RESUMO
UNLABELLED: Laccase isoenzymes (LacI,II,III) produced on wheat bran from Trametes hirsuta were partially purified through anion exchange chromatography. The three isoenzymes had the same MW of 65 kDa, and their main physico-chemical properties were studied. As single isoenzymes, laccases were unable to decolourize dye. Among several mediators evaluated, syringaldehyde was the most effective in dye decolourization (100%). A remarkable increase in dye decolourization was observed when LacI, II, III in mixture or crude enzyme were added to the reaction system, indicating that the laccases acted synergistically. SIGNIFICANCE AND IMPACT OF THE STUDY: Laccases have a great potential of application in bioremediation processes. White rot fungi produces several laccase isoenzymes and many of them have been purified and characterized. However, the additive or synergic action between laccase isoenzymes in dye decolourization has not yet been described. Such studies will help to better understand their action and to improve the process with isoenzymes mixtures. This study showed synergistic action between isoenzymes laccases produced by Trametes hirsuta Bm2 during decolourization of indigo carmine.