College of Food and Biological Engineering, Qiqihar University, Qiqihar, 161006, People's Republic of China.
Appl Biochem Biotechnol. 2019 Jun;188(2):410-423. doi: 10.1007/s12010-018-2927-8. Epub 2018 Nov 28.
In this study, a fungal and two yeast β-galactosidases were immobilized using alginate and chitosan. The biochemical parameters and lactose hydrolysis abilities of immobilized enzymes were analyzed. The pH optima of immobilized fungal β-galactosidases shifted to more acidic pH compared to free enzyme. Remarkably, the optimal temperature of chitosan-entrapped yeast enzyme, Maxilact, increased to 60 °C, which is significantly higher than that of the free Maxilact (40 °C) and other immobilized forms. Chitosan-immobilized A. oryzae β-galactosidase showed improved lactose hydrolysis (95.7%) from milk, compared to the free enzyme (82.7%) in 12 h. Chitosan-immobilized Maxilact was the most efficient in lactose removal from milk (100% lactose hydrolysis in 2 h). The immobilized lactases displayed excellent reusability, and chitosan-immobilized Maxilact hydrolyzed > 95% lactose in milk after five reuses. Compared to free enzymes, the immobilized enzymes are more suitable for cost-effective industrial production of low-lactose milk due to improved thermal activity, lactose hydrolysis efficiencies, and reusability.
在这项研究中，使用海藻酸钠和壳聚糖固定化了两种真菌和两种酵母β-半乳糖苷酶。分析了固定化酶的生化参数和乳糖水解能力。与游离酶相比，固定化真菌β-半乳糖苷酶的最适 pH 值向更酸性 pH 值偏移。值得注意的是，壳聚糖包埋酵母酶 Maxilact 的最适温度升高至 60°C，明显高于游离 Maxilact（40°C）和其他固定化形式。壳聚糖固定化 A. oryzae β-半乳糖苷酶在 12 小时内从牛奶中水解乳糖的效率（95.7%）高于游离酶（82.7%）。壳聚糖固定化 Maxilact 是从牛奶中去除乳糖最有效的（2 小时内 100%水解乳糖）。固定化乳糖酶具有优异的可重复使用性，壳聚糖固定化 Maxilact 在五次重复使用后仍能水解牛奶中的乳糖>95%。与游离酶相比，由于热活性、乳糖水解效率和可重复使用性的提高，固定化酶更适合用于经济高效地生产低乳糖牛奶。
