Enhanced Production Of Laccase Enzyme By The White-Rot Mushroom Fungus Pleurotus Florida Using Response Surface Methodology

Laccase is the chief ligninolytic enzyme produced by the white-rot mushroom fungi and it has several biotechnological applications including removal of toxic organo pollutants, dye degradation and in melanin synthesis. There is a growing need for isolation and identification of new laccase producing organisms to be used in industries. This paper reports that the increase in laccase production and activity in Pleurotus florida, an oyster mushroom species, in the presence of PAH (Anthracene) by using media engineering techniques and Statistical design experiments involving Response Surface Methodology. Central composite design was applied to optimize the media components and to evaluate the effect of peptone, malt extract and CaCl2 on laccase activity. This statistical design experiment aimed to reduce the number of experiments and to obtain more information on the mutual interactions between the variables. Central composite design led to 20 sets of experiments. When the optimized amounts of nutrients (Peptone, Malt Extract and CaCl2 was 1, 1, 0.1g respectively) were used as supplements to the basal salt medium, laccase activity obtained was increased ten fold (from 2.20 IU/ml to 22.6 IU/ml) over the control treatment using basal salt medium. The interaction between the three supplements as revealed by the RSM indicates that laccase activity was promoted when basal salt medium was supplemented with peptone, malt extract and CaCl2were in the ratio 1:1:0.1. The significant increase in laccase activity using response surface methodology demonstrates the bioprospecting potential of this isolate as a good source of laccase enzyme for industrial applications.