Adsorption of Tannase from Aspergillus ficuum to carboxyl-functionalized multi-walled carbon nanotubes

Abstract

The immobilization of cross-linked tannase onto carboxyl-functionalized multi-walled carbon nanotubes (MWCNT?COOH) was achieved via physical adsorption. Glutaraldehyde was used to cross-link the enzyme molecules. Spectroscopic and morphological characterizations of the enzyme-nanotubes composite were carried out, which authenticated the successful adsorption event. Enzyme composite is proven equal to-, or even superior than free tannase, in terms of catalytic activities and stabilities, when measured under different thermal-, pH-, and recycling conditions. Whilst both free- and immobilized tannase preparations exhibited optimum catalysis at pH 5.0 and 35?C, tannase-nanotubes composite possesses better thermal stability. The immobilized preparation retained 75% of its initial catalytic activity following ten consecutives use. The study demonstrated a facile method to produce catalytically-efficient nanobiocatalyst composite for biotechnological applications.