Immobilization of α-Amylase via Adsorption on Ordered Nanoporous Silica

One of the main directions of investigation in applied enzymology is to study the stability of the enzyme molecule. Immobilization, the process of fixing an enzyme into the specific spaces of inert support, is generally carried out so that the immobilized enzyme can be kept active during the reaction and re-use of the enzyme becomes possible as well.A variety of solids including gels, resins, zeolite or silica have been studied as enzyme immobilizing support [1]. Inorganic supports are superior to the organic supports in easily regeneration, cost-efficiency and the stable and controllable surface properties. The inorganic supports such as silica are known to be thermally and mechanically stable, nontoxic, and highly resistant against microbial attacks and organic solvents [2]. The discovery of ordered, high surface area mesoporous silicas (500–1200m2/g) in 1990s have opened one broad way for the immobilization of enzymes [1, 2].α-Amylase (EC 3.2.1.1) hydrolysis internal α -1,4 glucosidic linkages in starch by random attacks with retention of the anomeric configuration and produce a range of products such as glucose and maltose or specific malto-oligosaccharide or mixed malto-oligosaccharides depending on the sources of α-amylases. These hydrolysates are widely applied in the food, pharmaceutical and fine chemical industries as products such as maltose syrups. Amylases also play a significant role in starch, detergent, beverage and textile industries [3].In this study, silica with nano-sized pores was synthesized via sol-gel method to use as α-amylase support. Enzyme immobilization is done by adsorption techniques and the activity and stability of free and immobilized enzyme assayed and compared to each other