title: Enzyme immobilisation in permselective microcapsules.
abstract: The objective of this investigation was to study the permselective behaviour of calcium alginate membranes, including the modifying effects of silica additives, which were subsequently used as microcapsule shells. Diffusion experiments and HPLC were carried out to ascertain the size-exclusion property of the membranes for a mixed molecular-weight dextran solution. Hollow microcapsules containing the enzyme dextranase were prepared using double concentric nozzles and the encapsulation performance was evaluated based on an analysis of the enzyme reactivity and stability. To improve mass transport within the microcapsules, magnetic nanoparticles were introduced into the liquid core and agitated using an alternating external magnetic field. The modified membranes exhibited better size-exclusion behaviour than the unmodified membranes. The magnetic nanoparticles slightly improved mass transport inside the microcapsule. The encapsulated enzyme yielded nearly 80% of the free enzyme activity and retained about 80% of the initial catalytic activity even after being used for eight reaction cycles.
authors: Laboratory of Technical Chemistry B, Faculty of Bio- and Chemical Engineering, TU Dortmund, 44227 Dortmund, Germany. Pachariyanon.Pavadee@bci.tu-dortmund.de
authors: Pavadee
authors: P
authors: Pachariyanon
authors: Ekkehard
authors: E
authors: Barth
authors: David W
authors: DW
authors: Agar
mesh_terms: D000464:Alginates; D055162:Biocatalysis; D002214:Capsules / Q000737:chemistry* / Q000378:metabolism; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000378:metabolism; D020723:Glucuronic Acid; D006603:Hexuronic Acids; D058185:Magnetite Nanoparticles; D008567:Membranes, Artificial; D010539:Permeability; D012822:Silicon Dioxide
chemical_list: D000464:Alginates; D002214:Capsules; D004800:Enzymes, Immobilized; D006603:Hexuronic Acids; D058185:Magnetite Nanoparticles; D008567:Membranes, Artificial; D012822:Silicon Dioxide; D020723:Glucuronic Acid