Preliminary Production and Partial Purification of Laccase from a White Rot Fungus and Its Application in Dye Degradation

Abstract

In this study, a laccase producing white rot fungus from the wood degrading family of dermatophytic Trichophyton sp. was isolated. The laccase which was produced via solid state fermentation using rice bran as the lignocellulosic support was partially purified before its effectiveness in degrading an azo dye (methyl orange) was examined. Time course study showed that day nine (day 9) gave the maximum enzyme production. The crude laccase was purified by ammonium sulfate precipitation and dialyzed against sodium phosphate buffer pH 7. Optimum pH and temperature of the were 4.5 and 55°C respectively as assayed using ABTS (2,2 azino bis-3-ethyle benzothiozoline-6-sulfonic acid) as substrate. Dye degradation assay was carried out by introducing 0.5 ml of the enzyme into three dye concentrations: 50 mg/L, 100 mg/L and 200 mg/L and monitoring them for up to 48 hours by taking their absorbances at intervals at 5mins, 5hours, 24hours and 48 hours after enzyme introduction. At the end of the experiment, good dye degradation by laccase from Trichophyton sp. was observed to be positive with 50 mg/L being the most effective concentration during the study. The result are positive indicators of the fact that locally isolated white rot fungi has the capacity to be used for many biotechnological dye degradation and removal studies.