Luo Jian, Li Qian, Sun Xitong, Tian Jing, Fei Xu, Shi Feng, Zhang Nan, Liu Xiangli
Department of Bioengineering, Dalian Polytechnic University 116034 Dalian China
Dalian Institute of Chemical Physics, Chinese Academy of Sciences 116023 Dalian China
RSC Adv. 2019 Feb 5;9(8):4514-4520. doi: 10.1039/c9ra00075e. eCollection 2019 Jan 30.
Silica material has high specific surface area and excellent chemical stability, which make it useful for enzyme immobilization. In this work, naringinase was immobilized from fermentation broth of FFCC uv-11 by silica materials with different pore diameters of 2 nm (MCM-41), 7.7 nm (SBA-15) and 80 nm (silica gel). It was shown that SBA-15 had the highest naringinase activity, and this was chosen as a suitable carrier material for naringinase immobilization. First, SBA-15 was modified by glutaraldehyde at a concentration of 7% at 25 °C for 2 h, and it was then used for the immobilization of naringinase. At pH 3.5, the immobilized naringinase activity reached 467.62 U g at 40 °C for 4 h when the initial naringinase activity was 89.04 U mL. Furthermore, at the optimal reaction temperature of 45 °C and pH of 4.5, the binding efficiency, activity recovery rate and specific activity of the immobilized naringinase were 63.66%, 87.64% and 517.43 U g, respectively. Compared with free naringinase, in naringin hydrolysis, the immobilized naringinase performed over a wide pH application range and had good thermal stability. Even more important, the immobilized naringinase retained 61.81% of the residual naringinase activity after eight consecutive cycles, and kept 80.95% of the residual naringinase activity after one month of storage. This study provides an ideal carrier material and some basic data for naringinase immobilization technology, which will greatly promote the application of naringinase in industrial fruit juice processing.
二氧化硅材料具有高比表面积和优异的化学稳定性，这使其可用于酶固定化。在本研究中，采用孔径分别为2nm（MCM - 41）、7.7nm（SBA - 15）和80nm（硅胶）的二氧化硅材料从FFCC uv - 11的发酵液中固定化柚苷酶。结果表明，SBA - 15具有最高的柚苷酶活性，因此被选为柚苷酶固定化的合适载体材料。首先，将SBA - 15在25℃下用7%的戊二醛修饰2小时，然后用于固定化柚苷酶。在pH 3.5、40℃下反应4小时时，当初始柚苷酶活性为89.04U/mL时，固定化柚苷酶活性达到467.62U/g。此外，在最佳反应温度45℃和pH 4.5下，固定化柚苷酶的结合效率、活性回收率和比活性分别为63.66%、87.64%和517.43U/g。与游离柚苷酶相比，在柚苷水解过程中，固定化柚苷酶在较宽的pH应用范围内表现良好，且具有良好的热稳定性。更重要的是，固定化柚苷酶在连续八个循环后保留了61.81%的残余柚苷酶活性，在储存一个月后保留了80.95%的残余柚苷酶活性。本研究为柚苷酶固定化技术提供了理想的载体材料和一些基础数据，将极大地促进柚苷酶在工业果汁加工中的应用。
