Indigo degradation with laccases from Polyporus sp. and Sclerotium rolfsii

We have investigated the potential of fungal laccases from Polyporus sp. an d Sclerotium rolfsii to degrade insoluble indigo. Evidence shows that both laccases are able to oxidize insoluble indigo to give isatin (indole-2,3-di one), which further degrades to anthranilic acid (2-aminobenzoic acid). Ads orption studies show that the laccase from Polyporus sp. has a higher affin ity for indigo than the laccase of Sclerotium rolfsii. The particle size of indigo agglomerates is influenced by the origin of the laccase preparation and the incubation time: The potential of laccases to modify indigo staine d fabrics is assessed. Treatment of indigo dyed fabrics with laccase preven ts indigo backstaining, and Polyporus sp. appears to be more effective for reducing backstaining.