الفهرس 
Introduction and aim of the workOnly 14 pages are availabe for public view
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Abstract
Pleurotus ostreatus was proved to be efficient source for laccase production. Solid state medium containing rice bran, 2 ml spore suspention as the best inoculums size, pH 4.5, 0.5 KGy irradiation dose ,incubation at 30 oc were very appropriate conditions for the highest extracellular laccase production. Purification by anion exchange chromatography using DEAE sepharose and sephacryl HR are successful in purifying laccase.The molecular weight of laccase was 75 KDa determined by SDS- PAGE.The optimum pH for activity was 5 and for stability was (6.5-7.5), the optimum temperature for activity was 35oCand stability of the enzyme was 40oC , the enzyme retained 100% of its activity after 20 minutes incubation, 85% of its activity after 1 h incubation at the same temperature . Laccase was immobilized by microencapsulation into alginate, the immobilized laccase beads (2-3 mm) were formed, free laccase (35 U/ml) has higher activity than encapsulated laccase (24.3 U/ml).Purified laccase with specific activity of 348.8 U/mg and molecular weight of 75 KDa was used in the construction of biofuel cell with generated voltage of 0.22V immediately.