Abstract
With the extensive industrial applications of laccase in mind, this study was performed to investigate the decolorization applicability of sol-gel matrix-immobilized laccase. Indigenous G. leucidum laccase (592±6 U/mL) was purified 6.5-fold with a specific activity of 875 U/mg. The purified laccase had a molecular weight of 66 kDa, as evidenced by a single band on SDS-PAGE. Active laccase fractions were immobilized by entrapping in Sol-Gel matrix of trimethoxysilane (TMOS) and propyltetramethoxysilane (PTMS). A maximum of 90.7% immobilization efficiency was achieved with a purified fraction containing 2 mg/mL laccase. An activity profile revealed that immobilized laccase retained 78 to 80% of its original activity at a pH of 4 and a temperature of 80 °C, compared to free laccase. The tolerance capacity of laccase against inactivating agents (cystein, EDTA, and Ag+) was also enhanced by up to 80% by sol-gel immobilization. To explore the decolorization applicability, the immobilized laccase was tested against four different textile industry effluents. After the stipulated reaction time (24 h), varying decolorization percentages of wastewater effluents (with a maximum of 97.3% decolorization) were achieved.