Department of Food Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA.
Department of Food Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA.
Food Chem. 2018 Jun 15;251:115-124. doi: 10.1016/j.foodchem.2018.01.068. Epub 2018 Jan 9.
The conversion of whey permeates to galacto-oligosaccharides (GOS) was studied by the enzymatic action of β-galactosidase from Aspergillus oryzae in a continuous flow packed-bed reactor. A novel method of enzyme immobilization involving covalent immobilization of β-galactosidase on 3-aminopropyl triethoxysilane(3-APTES)-modified glass beads was developed by the cross-linking method. The pH and temperature dependence of the enzymatic efficiency of the glass bead-immobilized enzyme was compared with that of the free enzyme. Increased pH and thermal stabilities were observed for the immobilized enzyme versus the free enzyme. The reusability of the enzyme immobilized packed-bed reactor was studied and only about 4.6% of GOS yield was lost after eight reuses. Repeated cycle reactions were also carried out to improve the formation of GOS. The results showed that the GOS formation increased and a maximum GOS yield of 39.3% with 56.4% lactose conversion was obtained after the 2nd cycle of passing.
采用米曲霉β-半乳糖苷酶在连续流填充床反应器中酶促转化乳清制备半乳糖低聚糖（GOS）。通过交联法开发了一种新型酶固定化方法，即用 3-氨丙基三乙氧基硅烷（3-APTES）修饰的玻璃珠将β-半乳糖苷酶共价固定化。比较了固定化酶和游离酶的酶促效率对 pH 值和温度的依赖性。与游离酶相比，固定化酶表现出更高的 pH 值和热稳定性。研究了酶固定化填充床反应器的可重复使用性，经过 8 次重复使用后，GOS 的产率仅损失了约 4.6%。还进行了重复循环反应以提高 GOS 的生成量。结果表明，在第 2 次通过循环后，GOS 的生成量增加，乳糖转化率为 56.4%时，GOS 的最大产率为 39.3%。
