Optimization of nutritional factors and copper on laccase production by Pleurotus florida

Document Type : Research Paper

Authors

1 Department of plant pathology, Gorgan agricultural and natural resources university

2 Department of Plant Protection, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran

Abstract

Laccases as lignocellulolytic enzymes are commonly produced by submerged fermentation, but for more constructive production, it would be preceded by the nutritional factors suitable for the growth of the fungi. In the present study, overproduction of laccase activity by nutritional factor interactions was studied in Pleurotus florida, a white-rot fungi. Response surface methodology (RSM) based on Box-Behnken factorial design (BBD) was performed to optimize the interaction of glucose and yeast extract concentrations on maximum enzyme activity with and without copper sulfate, as an inducer. The results show a quadratic model with a very low p-value (<0.0001) to explain the changes in laccase production as a function of glucose, yeast extract, and copper sulfate concentrations. Based on the coefficient of determination (R2) and mean absolute error, the RSM model provided a good quality prediction for the laccase activity production with all independent variables. The findings explain a 1.4-1.5 logarithmic unit increase in laccase activity occurs in the presence of copper compared to cultures without copper with an optimal concentration of glucose and yeast extract as carbon and nitrogen sources, respectively. Maximum laccase activity was obtained using optimized conditions (18.20 gL-1 glucose, 8.22 gL-1 yeast extract, and 0.93 mM copper sulfate). This highlights the potential of the laccase production for utilization in biomass changeover systems.

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