Improvement of Laccase Production in Pluerotus pulmonarius-LAU 09 by Mutation

The strain improvement of P. pulmonarius LAU 09 for laccase production was carried out by UV- light exposure at 210nm (UV-sterilizer, Millipore xx63 70000) for 90minutes. The highest laccase activity of 2.5 Uml-1 was produced by LAU 90 (mutant) in comparison with obtained yield by wild type LAU 09 (1.75 Uml-1). The optimal physiological parameters for optimum laccase production by LAU 90 are 30OC of temperature, pH of 5.0 and incubation of 168hours. The mutant strain gave the highest total enzyme activity and enzyme specific activity of 71.7 x 10-4 mol/min and 89.63X 10-4 IU/mg of purified laccase enzyme respectively, with molecular weight of 97KDa. The activity of the purified enzyme was strongly inhibited by Sodium azide and EDTA at 1ml/0.1mM and 0.5ml/100mM respectively. The result obtained shown an improved performance of the mutant (LAU 90) strain of P. pulmonarius in laccase production over the wild (LAU 09) type.