Department of Biomaterial Control, Dong-Eui University, Busan 614-714, Korea.
J Microbiol Biotechnol. 2010 Mar;20(3):513-7.
A thermostable trehalose synthase (TtTSase) from Thermus thermophilus HJ6 was immobilized on chitosan activated with glutaraldehyde. The yield of immobilization was evaluated as 39.68%. The optimum pH of the immobilized enzyme was similar to that of the free enzyme. However, the optimal temperature ranges were shifted by about 4 degrees C owing to better thermal stability after immobilization. The half-life of heat inactivation for free and immobilized enzymes was 5.7 and 6.3 days at 70 degrees C, respectively, thus showing a lager thermostability of the immobilized enzyme. When tested in batch reaction, the immobilized enzyme retained its relative activity of 53% after 30 reuses of reaction within 12 days, and still retained 82% of its initial activity even after 150 days at 4 degrees C. A packed-bed bioreactor with immobilized enzyme showed a maximum yield of 56% trehalose from 100 mM maltose in a continuous recycling system (bed volume: 10 ml) under conditions of pH 7.0 and 70 degrees C.
嗜热脂肪地芽孢杆菌 HJ6 的热稳定海藻糖合酶（TtTSase）通过戊二醛活化壳聚糖进行固定化。固定化的产率评估为 39.68%。固定化酶的最适 pH 与游离酶相似。然而，由于固定化后热稳定性更好，最佳温度范围发生了约 4°C 的偏移。在 70°C 下，游离酶和固定化酶的热失活动力学半衰期分别为 5.7 和 6.3 天，因此固定化酶具有更大的热稳定性。在分批反应中，在 12 天内进行 30 次重复反应后，固定化酶保留了其相对活性的 53%，即使在 4°C 下放置 150 天后，仍保留了其初始活性的 82%。在 pH 值为 7.0 和 70°C 的条件下，在连续回收系统（床体积：10ml）中，使用固定化酶的填充床生物反应器从 100mM 麦芽糖中获得了 56%的海藻糖的最大产量。
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