Reversible immobilization of glucoamylase onto metal–ligand functionalized magnetic FeSBA-15

Magnetic SBA-15 (FeSBA-15) was prepared via wet impregnation, calcination and reduction, and p(glycidylmethacrylate) (PGMA) was grafted on the surface of FeSBA-15 using surface-initiated atom transfer radical polymerization (SI-ATRP) for a prescribed time. The epoxy groups of the PGMA were reacted with Cu(II) metal–ligand complex (i.e., imidazole or iminodiacetic acid) to form metal–chelate brush. Subsequently, the functionalized FeSBA-15 as a regenerated support was used for enzyme immobilization. Glucoamylase was immobilized as a model enzyme on the regenerated supports through metal-ion affinity interactions. The quality of glucoamylase immobilized on the regenerated supports is defined by determining of the enzyme activity, thermal stability, and reusability. The results indicate that the metal–chelate brushes offer an efficient route to immobilize enzymes via metal-ion affinity interactions. The applicability of the regenerated supports in the current study is relevant for the conjugation of other enzymes beyond glucoamylase.

► Magnetic FeSBA-15 mesoporous silica was chosen as the base of support. ► Polymer chains (PGMA) were grafted on the outer surfaces of magnetic FeSBA-15. ► PGMA was functionalized with imidazole or iminodiacetic acid. ► Functionalizable and metal–chelate surfaces for reversible enzyme immobilization. ► The regenerated biocatalyst still reserved its original performance.