Abstract

A great deal of works has been carried out assessing dye-decolorization capabilities of fungi, but only few species were investigated. In this present study, ten fungal species were screened for laccase activity by indicator plate method, of which five species were found to be laccase-positive. Laccase activity varied during growth and maximal laccase activity was observed during the 9^th day, except for Agaricus bisporus. Pleurotus ostreatus gave the highest laccase activities, showing average value around 570 U/L, which were higher than other strains. Addition of 1 mM copper sulphate induced the laccase production efficiently by 60 to 80%, while veratryl and benzyl alcohol induced laccase production in all the laccase positive species except for A.  bisporus. Constitutive expression of laccase was observed in F. solani in the presence of copper sulphate. In addition, the extracellular laccase from the P. ostreatus could decolorize reactive dyes, which suggests the potential application of laccase in textile effluent treatment.

Key words: Dyes, decolorization, inducer, laccase, Pleurotus, textile.