Abstract Purified Acetobacter tropicalis dextransucrase was immobilized in different matrices viz. calcium-alginate, κ-carrageenan, agar, agarose and polyacrylamide. Calcium-alginate was proved to be superior to the other matrices for immobilization of dextransucrase enzyme. Standardization of immobilization conditions in calcium-alginate resulted in 99.5% relative activity of dextransucrase. This is the first report with such a large amount of relative activity as compared to the previous reports. The immobilized enzyme retained activity for 11 batch reactions without a decrease in activity which suggested that enzyme can be used repetitively for 11 cycles. The dextransucrase was also characterized, which revealed that enzyme worked best at pH 5.5 and 37 °C for 30 min in both the free as well as immobilized state. Calcium-alginate immobilized dextransucrase of A. tropicalis showed the Km and Vmax values of 29 mM and 5000 U/mg, respectively. Free and immobilized enzyme produced 5.7 mg/mL and 2.6 mg/mL of dextran in 2 L bench scale fermenter under optimum reaction conditions. This immobilization method is very unconventional for purified large molecular weight dextran-free dextransucrase of A. tropicalis as this method is used usually for cells. Such reports on entrapment of purified enzyme are rarely documented.

中文翻译：

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从新分离的热带醋杆菌中捕获纯化的新型葡聚糖蔗糖酶及其与游离酶动力学参数的比较研究

摘要 纯化的热带醋杆菌葡聚糖蔗糖酶固定在不同的基质中。藻酸钙、κ-角叉菜胶、琼脂、琼脂糖和聚丙烯酰胺。海藻酸钙被证明在固定葡聚糖蔗糖酶方面优于其他基质。海藻酸钙固定条件的标准化导致葡聚糖蔗糖酶的相对活性为 99.5%。与之前的报告相比，这是第一份具有如此大量相关活动的报告。固定化酶在 11 个批次反应中保持活性而活性没有降低，这表明酶可以重复使用 11 个循环。还表征了葡聚糖蔗糖酶，这表明该酶在游离和固定状态下在 pH 5.5 和 37°C 下均能发挥最佳作用 30 分钟。热带放线菌的藻酸钙固定化葡聚糖蔗糖酶的 Km 和 Vmax 值分别为 29 mM 和 5000 U/mg。在最佳反应条件下，游离和固定化酶在 2 L 小规模发酵罐中产生 5.7 mg/mL 和 2.6 mg/mL 的葡聚糖。这种固定方法对于纯化的大分子量无葡聚糖葡聚糖蔗糖酶是非常非常规的，因为这种方法通常用于细胞。此类关于捕获纯化酶的报告很少被记录在案。热带，因为这种方法通常用于细胞。此类关于捕获纯化酶的报告很少被记录在案。热带，因为这种方法通常用于细胞。此类关于捕获纯化酶的报告很少被记录在案。