Strain improvement of Pleurotus citrinopileatus MTCC 1796 for enhanced production of laccase enzymes and its environmental application

The present study aims to improve a fungal strain; Pleurotus citrinopileatus MTCC 1796 to produce laccase by inducing mutation through ultraviolet (UV) light irradiation. The laccase from the wild and mutant strains was partial purified and it was found that the mutant cells of the strain produced laccase with higher activity (16.32 U/mL) while, the wild type produced laccase with an activity of 9.75 U/mL. The decolorization efficiency of the laccase from the wild and mutant strains was tested against Basic Blue 7 (BB7), belonging to the triarylmethane class of dyes. The decolorization of BB7 was high in the case of reactions catalyzed by the laccase from the mutant cells. The optimization of the BB7 decolorizing factors such as incubating temperature and pH for the varying BB7 concentration and time was studied. UV–Vis spectrophotometric and Fourier transform infrared spectroscopic analyses of BB7 decolorization and degradation by the laccase from the mutant cells was analyzed. Conclusively, the toxicity tests using plant seeds were done to understand the toxicity of the BB7 and the products of laccase catalyzed reactions were done.