Chen Luyi, Zhou Yuanlu, Lu Changxin, Ma Zhi, Chen Hanchi, Zhu Linjiang, Lu Yuele, Chen Xiaolong
Institute of Fermentation Engineering, Zhejiang University of Technology, Hangzhou, 18 Chaowang Road, Hangzhou, 310014, China.
College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, China.
Biotechnol Lett. 2021 Sep;43(9):1757-1764. doi: 10.1007/s10529-021-03100-6. Epub 2021 May 26.
l-Menthyl α-D-glucopyranoside (α-MenG) is a glycoside derivative of l-menthol with improved water-solubility and new flavor property as a food additive. α-MenG can be synthesized through biotransformation, but its scale-up production was rarely reported. In this study, the properties of an α-glucosidase from Xanthomonas campestris pv. campestris 8004 (Agl-2) in catalyzing the glucosylation of menthol was investigated. Agl-2 can almost completely glycosylate l-menthol (> 99%) when using 1.2 M maltose as glycosyl donor. Accumulated glucose resulted from maltose hydrolysis and transglycosylation caused the inhibition of the glucosylation rate (40% reduction of the glucosylation rate in the presence of 1.2 M glucose) which can be avoided through whole-cell catalysis with recombinant E. coli. Interestingly, in spite of the poor solubility of menthol, the productivity of α-MenG reached 24.7 g/(L·h) in a 2 L catalyzing system, indicating industrialization of the reported approach.
L-薄荷基α-D-吡喃葡萄糖苷（α-MenG）是L-薄荷醇的糖苷衍生物，作为食品添加剂，其水溶性得到改善，具有新的风味特性。α-MenG可通过生物转化合成，但很少有关于其放大生产的报道。在本研究中，对野油菜黄单胞菌野油菜致病变种8004（Agl-2）的一种α-葡萄糖苷酶催化薄荷醇糖基化的特性进行了研究。当使用1.2 M麦芽糖作为糖基供体时，Agl-2几乎可以使L-薄荷醇完全糖基化（>99%）。麦芽糖水解和转糖基化产生的葡萄糖积累导致糖基化速率受到抑制（在1.2 M葡萄糖存在下糖基化速率降低40%），这可以通过重组大肠杆菌全细胞催化来避免。有趣的是，尽管薄荷醇的溶解度较差，但在2 L催化体系中，α-MenG的生产率达到了24.7 g/(L·h)，表明所报道的方法具有工业化潜力。
