Industry Department and Organic Chemistry Department, Faculty of Exact and Natural Sciences, University of Buenos Aires and National Council of Scientific and Technical Research, Buenos Aires, Argentina.
Biomacromolecules. 2011 Sep 12;12(9):3147-55. doi: 10.1021/bm2009075. Epub 2011 Aug 18.
Several alternatives to the conventional alginate beads formulation were studied for encapsulation of invertase. Pectin was added to the alginate/enzyme solution while trehalose and β-cyclodextrin were added to the calcium gelation media. The effect of composition changes, freezing, drying methods (freeze, vacuum, or air drying), and thermal treatment were evaluated on invertase stability and its release kinetics from beads. The enzyme release mechanism from wet beads depended on pH. The addition of trehalose, pectin, and β-cyclodextrin modified the bead structure, leading in some cases to a release mechanism that included the relaxation of the polymer chains, besides Fickian diffusion. Enzyme release from vacuum-dried beads was much faster than from freeze-dried beads, probably due to their higher pore size. The inclusion of β-cyclodextrin and especially of pectin prevented enzyme activity losses during bead generation, and trehalose addition was fundamental for achieving adequate invertase protection during freezing, drying, and thermal treatment. Present results showed that several alternatives such as drying method, composition, as well as pH of the relese medium can be managed to control enzyme release.
几种海藻酸钠珠粒制剂的替代方法被用于包埋转化酶。在海藻酸钠/酶溶液中添加果胶，在钙离子凝胶化介质中添加海藻糖和β-环糊精。考察了组成变化、冷冻、干燥方法（冷冻、真空或空气干燥）以及热处理对转化酶稳定性及其从珠粒中释放动力学的影响。湿珠粒中酶的释放机制取决于 pH 值。添加海藻糖、果胶和β-环糊精改变了珠粒的结构，在某些情况下，除了菲克扩散之外，还包括聚合物链的松弛，导致释放机制发生变化。真空干燥珠粒的酶释放速度比冷冻干燥珠粒快得多，这可能是由于其孔径更大。β-环糊精和特别是果胶的包含防止了酶在珠粒生成过程中的活性损失，并且海藻糖的添加对于在冷冻、干燥和热处理过程中实现足够的转化酶保护至关重要。目前的结果表明，可以通过干燥方法、组成以及释放介质的 pH 值等多种替代方法来控制酶的释放。
