Laccase production using mixed substrates containing lignocellulosic materials by Pleurotus ostreatus in submerged liquid culture

Enhanced production of the industrially important enzyme laccase from the white rot fungus Pleurotus ostreatus MTCC1804 was performed in the submerged liquid culture. The preliminary media component indispensable to increase the laccase production were screened by the classical or one factor at a time technique. The consequence of different lignocellulosic substrates on laccase production in single and combined or mixed substrate mode were investigated under controlled fermentation conditions. From the experimental study it was revealed that, the mixed substrates including rice bran, sugarcane bagasse and glucose rendered maximum laccase activity of 6471U/l than the productivities of individual substrates. Screening of the appropriate nitrogen source permitted to substantial improvement in the laccase production of 8433 U/l by the combined nitrogen sources viz, yeast extract and L-aspargine monohydrate of organic nitrogen sources. The stimulatory effect of various aromatic inducers on the production of extracellular laccase yield was observed. Out of eleven aromatic inducers explored, 2,5 xylidine enhanced the laccase production to 17542 U/l. The statistical analysis for screening of essential media components by Plackett-Burman design was implemented and maximum laccase production of 37452 U/l was obtained in the 9^th day of fermentation process.