Xylanase immobilized nanoporous gold as a highly active and stable biocatalyst

Dealloyed nanoporous gold, a nanostructured metallic sponge with tunable porosity and excellent biocompatibility, was employed as an effective support material for xylanase immobilization. Structure analyses revealed that the immobilization of xylanase was realized via chemical bonding of sulfur end-groups with gold surface atoms. The activity and stability for the immobilized enzyme were investigated under different conditions. And the immobilized enzymes were found to keep as high as 80% of the activity of free ones. Notably, these novel nanobiocatalysts showed quite impressive stability. Even after ten reaction cycles, this bio-nanocomposite could still retain ∼60% of the initial activity.

The morphology and composition of nanoporous gold before and after immobilized xylanase are verified by SEM and EDS, which providing a primary evidence of successful enzyme immobilization on the nanobiocatalyst.Figure optionsDownload as PowerPoint slideHighlights
► Xylanase-nanoporous gold was fabricated as an interesting type of ‘green biocatalyst’.
► It presents highly activity and stability.
► It is easy in the preparation and separation.
► It is efficient and cost-effective.
► The carrier, nanoporous gold, is a tunable porous structure to accommodate difference enzymes.