Isolation of laccase producing fungus from compost soil and partial characterization of laccase

The current study includes isolation of laccase producing fungus from compost soil and characterization of the laccase enzyme. In our study, 11 fungal isolates were isolated by serial dilution. They were cultivated on potato dextrose agar (PDA) plate with indicator compound 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) to screen for the laccase production ability. Out of 11 isolates, one was presumed to be potent, another showed medium potency, and three showed weak laccase producing ability. The most potent strain was used for further studies. Different carbon source, nitrogen source and pH optimization was carried out. It was found that laccase was active over a wide range of temperature and pH. The protein determination assay showed that the most favorable carbon source and nitrogen sources were maltose and casein respectively with pH range (5-6). The laccase activity was highest with maltose as carbon source and peptone as nitrogen source at pH 4. Further dye decolorization was performed with the fungal laccase produced in the broth culture.