Optimal immobilization of Trichoderma asperellum laccase on polymer coated Fe3O4@SiO2 nanoparticles for enhanced biohydrogen production from delignified lignocellulosic biomass

•Trichoderma asperellum laccase immobilized on chitosan coated Fe3O4@SiO2 NPs.•Process parameters for laccase immobilization on NPs were optimized by RSM.•Optimized conditions showed laccase immobilization efficiency of 91.23% in 5.3 h.•70% activity was obtained after 8 consecutive cycles of delignification.•Increased biohydrogen production was obtained from delignified biomass in CSTR.