Immobilization of laccase on modified Fe3O4@SiO2@Kit-6 magnetite nanoparticles for enhanced delignification of olive pomace bio-waste.

Lignocellulose is considered a major source for the production of valuable chemicals. Efficient degradation of lignin as the natural carrier of the lignocellulosic biomass represents a key limiting factor in biomass digestibility. Recently, biological delignification methods have been promoted as sustainable and environmentally friendly alternatives to the traditional technologies. In this study, porous nanocomposite of Fe3O4@SiO2@KIT-6 with magnetic properties was synthesized. The immobilized laccase supported on nanocomposite with enhanced stability in a hydrophobic ionic liquid has been developed for both olive pomace delignification and degradation of phenolic extracts from the pomace. After 6h incubation, the degradation rate of lignin and phenol by the immobilized laccase was estimated to be 77.3% and 76.5%, respectively. The immobilized laccase retained 70% of its initial degradation ability after 11 successive batch treatments of olive pomace. Furthermore, the immobilized laccase retained >70% of its initial activity after 21days of storage at room temperature. The obtained results indicated that the immobilized laccase on magnetic mesoporous support together with (1-Butyl-3-methylimidazolium hexafluorophosphate) ([Bmim][PF6]) could potentially provide a promising procedure for an improved enzymatic degradation of lignin and phenol in the related industries.