Garuba Emmanuel O, Onilude A
Microbial Physiology and Biochemistry Laboratory, Department of Microbiology, University of Ibadan, Nigeria.
J Genet Eng Biotechnol. 2018 Dec;16(2):341-346. doi: 10.1016/j.jgeb.2018.03.009. Epub 2018 Apr 4.
In this study, attempts were made to immobilize purified exo-inulinase from mutant thermophic -U4 onto Kaolinite clay by covalent bonding cross-linked with glutaraldehyde with an immobilization yield of 66% achieved. The free and immobilized inulinases were then characterized and characterization of the enzymes revealed that temperature and pH optima for the activity of the free and immobilized enzymes were both 65 °C and pH 4.5 respectively. The free inulinase completely lost its activity after incubation at 65 °C for 6 h while the immobilized inulinase retained 16.4% of its activity under the same condition of temperature and incubation time. The estimated kinetic parameters and for the free inulinase as estimated from Lineweaver-Burk plots were 0.39 mM and 4.21 µmol/min for the free inulinase and 0.37 mM and 4.01 µmol/min for the immobilized inulinase respectively. Inulin at 2.5% (w/v) and a flow rate of 0.1 mL was completely hydrolysed for 10 days at 60 °C in a continuous packed bed column and the operational stability of the system revealed that the half-life of the immobilized inulinase was 51 days. These properties make the immobilized exo-inulinase from -U4 a potential candidate for the production of fructose from inulin hydrolysis.
在本研究中，尝试通过戊二醛共价交联将突变嗜热菌 -U4 纯化的外切菊粉酶固定在高岭土上，固定化产率达到66%。然后对游离和固定化菊粉酶进行了表征，酶的表征显示游离和固定化酶活性的最适温度和pH分别为65℃和pH 4.5。游离菊粉酶在65℃孵育6小时后完全失去活性，而固定化菊粉酶在相同温度和孵育时间条件下保留了16.4%的活性。根据Lineweaver-Burk图估计的游离菊粉酶的动力学参数 和 分别为0.39 mM和4.21 μmol/min，固定化菊粉酶分别为0.37 mM和4.01 μmol/min。在连续填充床柱中，2.5%（w/v）的菊粉和0.1 mL的流速在60℃下10天完全水解，系统的操作稳定性表明固定化菊粉酶的半衰期为51天。这些特性使来自 -U4的固定化外切菊粉酶成为菊粉水解生产果糖的潜在候选物。
