Effects of Reaction Operation Policies on Properties of Core–Shell Polymer Supports Used for Preparation of Highly Active Biocatalysts

摘要

Core-shell polymer supports with different morphological features and compositions are prepared through combined suspension and emulsion polymerizations. It is shown that proper manipulation of the divinylbenzene (DVB) feed content allows for maximization of specific areas, porosities, and mechanical resistances. Additionally, it is shown that feeding of previously prepared miniemulsions leads to core-shell particles with smaller specific areas, due to less efficient coating of the cores. Particularly, the combined manipulation of polymerization times and DVB feed compositions allows for production of particles with pronounced specific area (50 m(2) g(-1)) and porosity (0.30 cm(3) g(-1)). Produced core-shell polymer particles are employed as supports for the immobilization of lipase B from Candida antarctica, and the obtained enzymatic activities for both hydrolysis (A(hyd)) and esterification (A(est)) reactions are very high (A(hyd) = 34.7 +/- 3.8 U/g; A(est) = 3564.6 +/- 581 U/g), even when compared to activities obtained using the reference commercial biocatalyst Novozym 435 (A(hyd) = 7.6 +/- 1.8 U/g, A(est) = 2384.7 +/- 307.2 U/g). Finally, biocatalysts prepared with the core-shell supports present higher enzymatic activities than biocatalysts prepared with supports of higher specific area obtained through conventional emulsion polymerizations, indicating that the porous structure of the shell can be beneficial for the immobilization and activity of the enzymes.