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 similar to 60% of the initial activity. (C) 2012 Elsevier Inc. All rights reserved.