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Poly(vinyl alcohol) (PVA) was modified with 3-aminopropyltriethoxysilane and was used for synthesis of poly(urethane-urea) microcapsules (PUUMc) with encapsulated maltogenic a-amylase (BaMa) (E. C. 3.2.1.133). The optimization of PVA modification factors and PUUMc synthesis conditions was performed. Chemical structure, porosity and thermostability of PUUMc which were obtained under various synthesis conditions were evaluated. Release rate of BaMa from PUUMc was slower and EI of BaMa was higher, when enzyme was encapsulated during PUUMc synthesis. [ABSTRACT FROM AUTHOR]

The novel poly(urethane–urea) microcapsules (PUUMC) were obtained by the interfacial polyaddition reaction between the oil-soluble hexamethylene diisocyanate (HMDI) and the water soluble poly(vinyl alcohol) (PVA) in a water-in-oil (W/O) emulsion. The PVA was used instead of diols. Maltogenase L (maltogenic α-amylase fromBacillus stearothermophilus(E. C. 3.2.1.133) (MG) was encapsulated in the PUUMC during or after formation of capsules. The PUUMC were thoroughly characterised by chemical analytical methods, FT-IR, SEM, thermal analysis, surface area, pore volume and size analysis. Furthermore, by carefully analysing the influencing factors including: catalyst and surfactants and their concentrations, the initial molar ratio of PVA and HMDI, stirring rate and ratio of dispersed phase to external phase, the optimum synthesis conditions were found out. A controlled release of MG could be observed in many cases. Delayed-release capsules were obtained when initial concentration of HMDI was increased. These capsules have potential application in biotechnology for saccharification of starch. [ABSTRACT FROM PUBLISHER]