Decolorization of orange G by Pleurotus ostreatus monokaryotic isolates with different laccase activity

The effect of enhanced laccase (Lac) activity (obtained after copper addition to cultivation media) on decolorization of azo dye Orange G in two basidiospore-derived monokaryotic isolates of Pleurotus ostreatus was determined. The high Lac-producing isolate efficiently decolorized Orange G. The low-producing isolate showed only poor decolorization ability during cultivation in liquid medium and no decolorization on agar plates containing Orange G after a 25-d growth. A substantial enhancement of Lac activity caused by copper addition into cultivation media was detected in both isolates but, at the same time, the biomass production decreased and decolorization rate was reduced.