Temperature-sensitive latex particles for immobilization of α-amylase

Poly(methyl methacrylate-co-N-isopropylacrylamide-co-N-acryloxysuccinimide) (poly(MMA/NIPAAm/NAS)) latex particles were prepared by emulsifier-free emulsion polymerization. The latex particles could reversibly flocculate and disperse when the solution temperature was kept above and below the characteristic lower critical solution temperature (LCST). The LCST of the latex dispersion could be adjusted lower or higher by increasing or decreasing, respectively, the ionic strength of the solution. α-Amylase was immobilized onto the latex particles by reacting with the succinimide groups on NAS. It was demonstrated that the α-amylase immobilized latex particles could be separated by thermoflocculation. After 5 repeated thermocycles, 83 % of the latex particles could be recovered, and the apparent enzymatic activity could be retained as high as 78 %.