Wang Hsueh-Ting, Yang Jin-Tong, Chen Kuan-I, Wang Tan-Ying, Lu Ting-Jang, Cheng Kuan-Chen
Graduate Institute of Food Science and Technology National Taiwan University Taipei Taiwan, ROC.
Institute of Biotechnology National Taiwan University Taipei Taiwan, ROC.
Food Sci Nutr. 2019 Jan 29;7(2):834-843. doi: 10.1002/fsn3.932. eCollection 2019 Feb.
An immobilized enzyme system for bioconversion of Lo Han Kuo (LHK) mogrosides was established. β-Glucosidase which was covalently immobilized onto the glass spheres exhibited a significant bioconversion efficiency from pNPG to pnitrophenol over other carriers. Optimum operational pH and temperature were determined to be pH 4 and 30°C. Results of storage stability test demonstrated that the glass sphere enzyme immobilization system was capable of sustaining more than 80% residual activity until 50 days, and operation reusability was confirmed for at least 10 cycles. The Michaelis constant ( ) of the system was determined to be 0.33 mM. The kinetic parameters, rate constant () at which Mogrosides conversion was determined, the in which 50% of mogroside V deglycosylation/mogroside IIIE production was reached, and the complete of complete mogroside V deglycosylation/mogroside IIIE production, were 0.044/0.017 min, 15.6/41.1 min, and 60/120 min, respectively. Formation of the intermediates contributed to the kinetic differences between mogroside V deglycosylation and mogroside IIIE formation.
建立了一种用于罗汉果（LHK）甜苷生物转化的固定化酶系统。共价固定在玻璃珠上的β-葡萄糖苷酶相对于其他载体表现出从对硝基苯-β-D-吡喃葡萄糖苷（pNPG）到对硝基苯酚的显著生物转化效率。确定最佳操作pH和温度分别为pH 4和30°C。储存稳定性测试结果表明，玻璃珠酶固定化系统能够在50天内维持超过80%的残余活性，并且确认操作可重复使用至少10个循环。该系统的米氏常数（）确定为0.33 mM。动力学参数，即确定罗汉果甜苷转化的速率常数（）、达到50%罗汉果甜苷V去糖基化/罗汉果甜苷IIIE产生时的（）以及罗汉果甜苷V完全去糖基化/罗汉果甜苷IIIE产生的完全（），分别为0.044/0.017 min、15.6/41.1 min和60/120 min。中间体的形成导致了罗汉果甜苷V去糖基化和罗汉果甜苷IIIE形成之间的动力学差异。
