Extracellular Laccase Production in Submerged Culture of Some White-Rot Fungi and Their Impact for Textile Dyes Decolorisation

White-rot fungi are a group of organisms capable of biodegrading lignin due to production of a ligninolytic enzyme complex. This enzyme complex is rich in several laccase isoenzymes which found to have the ability to decolorize different classes of industrial dyes. Laccases (EC 1.10.3.2) are phenol oxidases that catalyse one-electron oxidation of many aromatic substrates. This study aimed to evaluate extracellular laccase production in submerged culture of some white-rot fungi and their potential to decolorized three textile dyes like Bemacid red (BR), Bemacid yellow (BY) and Bemacid blue (BB). We found that the best laccase producing fungi were Pleurotus ostreatus var. Florida, Ganodrema applanatum, and Trametes versicolor. Enzyme production by selected strains was recorded in six different culture media: malt extract (ME), potato dextrose (PD), mushroom complete medium (MCM), potato-malt-peptone (PMP), glucose - malt extract - yeast (GMY) and yeast - malt extract (YM). T. versicolor and P. ostreatus showed the highest laccase activities in malt extract medium. Laccase activity and dyes discoloration in submerged cultures were determined spectrophotometrically. All fungal strains were able to discolouring BB dye. These studies underline the need to explore more laccase-producing fungi which could be involved in the textile dyes degradation.