State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China; Department of Food Science and Technology, Faculty of Engineering and Technology, University of Gezira, P.O. Box 20, Wad Madani, Sudan.
State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China.
Ultrason Sonochem. 2014 Jul;21(4):1325-34. doi: 10.1016/j.ultsonch.2014.02.004. Epub 2014 Feb 15.
In this research work, dextranase was immobilized onto calcium alginate beads by the combination of ultrasonic irradiation and high hydrostatic pressure (US/HHP) treatments. Effects of US/HHP treatments on loading efficiency and immobilization yield of dextranase enzyme onto calcium alginate beads were investigated. Furthermore, the activities of immobilized enzymes prepared with and without US/HHP treatments and that prepared with ultrasonic irradiation (US) and high hydrostatic pressure (HHP), as a function of pH, temperature, recyclability and enzyme kinetic parameters, were compared with that for free enzyme. The maximum loading efficiency and the immobilization yield were observed when the immobilized dextranase was prepared with US (40 W at 25 kHz for 15 min) combined with HHP (400 MPa for 15 min), under which the loading efficiency and the immobilization yield increased by 88.92% and 80.86%, respectively, compared to immobilized enzymes prepared without US/HHP treatment. On the other hand, immobilized enzyme prepared with US/HHP treatment showed Vmax, KM, catalytic and specificity constants values higher than that for the immobilized enzyme prepared with HHP treatment, indicated that, this new US/HHP method improved the catalytic kinetics activity of immobilized dextranase at all the reaction conditions studied. Compared to immobilized enzyme prepared either with US or HHP, the immobilized enzymes prepared with US/HHP method exhibited a higher: pH optimum, optimal reaction temperature, thermal stability and recyclability, and lower activation energy, which, illustrating the effectiveness of the US/HHP method. These results indicated that, the combination of US and HHP treatments could be an effective method for improving the immobilization of enzymes in polymers.
在这项研究工作中，通过超声辐射和高静压（US/HHP）处理的组合，将葡聚糖酶固定在海藻酸钠珠上。研究了 US/HHP 处理对葡聚糖酶在海藻酸钠珠上的装载效率和固定化产率的影响。此外，还比较了未经 US/HHP 处理、经超声（US）和高静压（HHP）处理以及经 US/HHP 处理制备的固定化酶的活性与游离酶的活性，考察了其在 pH 值、温度、可重复使用性和酶动力学参数方面的差异。当固定化的葡聚糖酶采用 US（25 kHz 时 40 W 处理 15 min）与 HHP（400 MPa 处理 15 min）联合处理时，观察到最大的装载效率和固定化产率，与未经 US/HHP 处理制备的固定化酶相比，装载效率和固定化产率分别提高了 88.92%和 80.86%。另一方面，与未经 US/HHP 处理制备的固定化酶相比，经 US/HHP 处理制备的固定化酶表现出更高的 Vmax、KM、催化和特异性常数值，表明这种新的 US/HHP 方法提高了所有研究反应条件下固定化葡聚糖酶的催化动力学活性。与经 US 或 HHP 处理制备的固定化酶相比，经 US/HHP 处理制备的固定化酶具有更高的：最适 pH 值、最佳反应温度、热稳定性和可重复使用性，以及更低的活化能，这说明了 US/HHP 方法的有效性。这些结果表明，US 和 HHP 处理的结合可以是一种有效的提高酶在聚合物中固定化的方法。
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