The catalytic activity of laccase immobilized in sol-gel silica

Abstract

The removal potentially harmful chemicals such as substituted phenols and aromatic amines by laccase oxidative biocatalyst has been attracting interest, particularly in view of certain unsolved problems of oxidation reactions in conventional chemical process. These environmental pollutants mostly do not dissolve in an aqueous solution due to their high hydrophobicity, hence organic solvents are required to dissolve and concentrate them. The biodegradation of these pollutants using enzymatic process has been hindered by instability of enzyme in organic solvents. In order to increase enzyme stability, several methods of stabilization through immobilization and encapsulation have been reported successfully for various enzymes. Enzyme immobilization by physical entrapment has a wide benefit and may provide relatively small perturbation of the enzyme native structure and function. Therefore, in afford to enhance the laccase activity and stability; encapsulation of laccase by sol-gel silica method was studied. The catalytic activity of laccase immobilized in sol-gel silica was demonstrated by an enzymatic assay using 2, 6-dimethoxyphenol as a substrate. After immobilization, the laccase was proven to be active in a wider pH range and the laccase loading in sol-gel silica has a significant effect on laccase activity.