Dodecenyl succinylated alginate as a novel material for encapsulation and hyperactivation of lipases

Alginate was modified with dodecenyl succinic anhydride (SAC12) in an aqueous reaction medium at neutral pH. The highest degree of succinylation (33.9 ± 3.5%) was obtained after 4 h at 30 °C, using four mole SAC12 per mol alginate monomer. Alginate was modified with succinic anhydride (SAC0) for comparison, and the structures and thermal properties of alg-SAC0 and alg-SAC12 were evaluated using FTIR, 1H NMR, and DSC. Calcium-hydrogel beads were formed from native and modified alginates, in which lipases were encapsulated with a load of averagely 76 μg lipase per mg alginate, irrespective of the type of alginate. Lipases with a “lid”, which usually are dependent on interfacial activation, showed a 3-fold increase in specific activity toward water-soluble substrates when encapsulated in alg-SAC12, compared to the free lipase. Such hyperactivation was not observed for lipases independent of interfacial activation, or for lipases encapsulated in native alginate or alg-SAC0 hydrogels.