Abstract

Saqib Hussain Hadri , Muhammad Javaid Asad , Muhammad Gulfraz , Muhammad Asghar , Nasir Mahmood Minhas , Raja Tahir Mahmood , Shehnaz Zakia and Nasir Mahmood

Laccase is the enzyme that has many industrial and biotechnological. Keeping in mind the importance of this enzyme on commercial and industrial levels, the present study was designed to optimize laccase production by Neurospora sitophila using agro-wastes including rice straw, sugarcane bagasse and corn cobs. Among the different conditions optimized, for the enhanced production of the laccase, include fermentation period, moisture level and inoculum size and were found to be 96 hours, 70% (for corn cobs and rice straw), 60% (for sugarcane bagasse) and 5mL respectively. Peptone, yeast extract and tween-20 were used as nitrogen source, inducer and surfactant respectively, to check their effect on the production of laccase. Peptone had negative effect in all concentrations while 0.4 % yeast extract and 0.2 % tween-20 enhanced the laccase production. Ammonium sulfate was used for the partial purification of the laccase and 60% ammonium sulfate was found to be the best concentration for this purpose with a 7.5 fold increase in the laccase activity as compared to the crude extract while using corn cobs as agriculture waste. Protein concentration of crude extract and after each purification step was determined by Biuret-protein assay. Optimum temperature and pH for the laccase activity were found to be 30oC and 5 respectively. Km and Vmax using guaiacol were found to be 0.666mM and 20.8 µM/min respectively.