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

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 degrees C, tannase-nanotubes composite possesses better thermal stability. The immobilized preparation retained 75 % of its initial catalytic activity following ten consecutive uses. The study demonstrated a facile method to produce catalytically efficient nanobiocatalyst composite for biotechnological applications.