Biodegradation of synthetic dyes by Irpex lacteus under various growth conditions

Degradability of azo-, anthraquinone- and Cu-phthalocyanine dye structures was studied using 39 strains of ligninolytic fungi, of which 60% could attack azo dyes, compared with 80–90% capable of attacking the other dyes. Irpex lacteus was shown to decolorize a number of various azo-, anthraquinone-, thiazine-, triphenylmethane- and phthalocyanine dyes at a concentration of 200 mg l−1 in stationary liquid culture. Decolorization levels after two weeks were 60–100%. Selective inhibition of manganese-dependent peroxidase (MnP) and laccase by sodium azide and n-propyl gallate indicated the involvement of MnP in decolorization of anthraquinone- and azo dyes. Immobilized on pinewood cubes, I. lacteus decolorized 100% of Remazol Brilliant Blue R (150 mg l−1) within six days. It also efficiently decolorized textile industry effluents containing color mixtures Drimarene Blue, Drimarene Red, Remazol Green and Acid Black, achieving 100%, 80%, 45% and 35% decolorization, respectively, within 3–5 days.