Stabilized Laccase on Ordered Mesoporous Silica

In 1992, a new class of mesoporous material (OMMs) was developed by the Mobil research group. This type of material possesses high surface area (700–1000 m2 g−1), high pore volume (approximately 1.0 ml g−1) and a well ordered pore structure. The unique structural properties of OMMs materials were thought to provide excellent supports for catalysts, such as metal oxides, organometallic compounds and even enzymes [1, 2].In 1998, Zhao et al. [3] reported a route for synthesizing mesoporous molecular sieves with pore sizes considerably larger than traditional MCM41, that still possess a highly ordered hexagonal array of channels, which involved the use of a coblock polymeric surfactant as template. The increase in pore size up to 300 Å should make these materials more suitable for enzyme immobilization.Laccases (p-diphenol oxidases, EC 1.10.3.2) belong to the family of multicopper oxidases that catalyze the oxidation of various aromatic substances, such as diphenols, aryl amines, and amino phenols, with the concomitant reduction of O2 to H2O [4]. It is commonly accepted that the Laccase oxidize aromatic compounds with a phenolic functional group. However, the overlapping substrate specificity of these enzymes can be extended to nonphenolic aromatic compounds with the use of aromatic called redox mediators; Laccase can oxidize veratryl and benzyl alcohols, nonphenolic groups of the lignin polymer, and lignin model substances [5].The aim of this research is adsorption of Laccase on external surfaces of mesoporous silica which synthesized in a basic aqueous reaction mixture consisting of tetraethyl orthosilicate (TEOS) as silica source, cetylpyridinium chloride as a structure-directing agent