Immobilization of the exo-maltohexaohydrolase by the irradiation method

Maltooligosaccharides: Properties, Production and Applications

Maltooligosaccharides (MOS) are homooligosaccharides that consist of 3-10 glucose molecules linked by α-1,4 glycosidic bonds. As they have physiological functions, they are commonly used as ingredients in nutritional products and functional foods. Many researchers have investigated the potential applications of MOS and their derivatives in the pharmaceutical industry. In this review, we summarized the properties and methods of fabricating MOS and their derivatives, including sulfated and non-sulfated alkylMOS. For preparing MOS, different enzymatic strategies have been proposed by various researchers, using α-amylases, maltooligosaccharide-forming amylases, or glycosyltransferases as effective biocatalysts. Many researchers have focused on using immobilized biocatalysts and downstream processes for MOS production. This review also provides an overview of the current challenges and future trends of MOS production.

A study on the thermostability of microencapsulated glucose oxidase

Glucose oxidase was microencapsulated within polyurea membranes by the interfacial polymerization method and the stability to heat of the encapsulated enzyme was examined. Thermostability of microencapsulated glucose oxidase was prominent and increased with increase in the amount of glucose oxidase entrapped. This stability, however, could not be ascribed to the peculiar properties of microcapsules but was suggested to be caused by the incorporation of glucose oxidase molecules in the membranes through chemical bonding. This stability revealed that the enzyme molecules in the microcapsules could not always exist in the dissolved form but a fairly large portion of the molecules participated in the polymerization reaction and changed their enzymatic properties.

Radiation-induced polymerization for the immobilization of penicillin acylase

The immobilization of Escherichia coli penicillin acylase (EC 3.5.1.11) was investigated by radiation-induced polymerization of 2-hydroxyethyl methacrylate at low temperature. A leak-proof composite that does not swell in water was obtained by adding the cross-linking agent trimethylolpropane trimethacrylate to the monomer-aqueous enzyme mixture. Penicillin acylase, which was immobilized with greater than 70% yield, possessed a higher Km value toward the substrate 6-nitro-3-phenylacetamidobenzoic acid than the free enzyme form (Km = 1.7 X 10(-5) and 1 X 10(-5) M, respectively). The structural stability of immobilized penicillin acylase, as assessed by heat, guanidinium chloride, and pH denaturation profiles, was very similar to that of the free-enzyme form, thus suggesting that penicillin acylase was entrapped in its native state into aqueous free spaces of the polymer matrix.