Isolation and culture optimization of extracellular Laccase enzymes of Pleurotus pulmonarius in submerged fermentation

P. pulnonarius produced laccase enzymes extracellularly both in stationary as well as in shaking condition. To obtain the optimum laccase production different cultural parameters were studied. Different carbon sources, nitrogen sources, and pH of the media showed differential influencing effect on laccase production. The laccase production was optimum in PSP (20% potato extract, 2% sucrose, 0.5% peptone) medium in pH 5.0. The value was 72.9 U/ml when measured using guaiacol as substrate. The enzyme showed more affinity towards ABTS than o-dianisidine or guaiacol. Three laccase isoenzymes were found in activity staining of the dialysed extracellular culture filtrate. Laccase isolated from P. pulmonaris can decolorised synthetic dyes (phenol red and malachite green) which were generally used in textile industries.