Abstract：
This study characterizes the acceptor specificity of levansucrases (LSs) from Gluconobacter oxydans (LS1), Vibrio natriegens (LS2), Novosphingobium aromaticivorans (LS3), and Paraburkholderia graminis (LS4) using sucrose as fructosyl donor and selected phenolic compounds and carbohydrates as acceptors. Overall, V. natriegens LS2 proved to be the best biocatalyst for the transfructosylation of phenolic compounds. More than one fructosyl unit could be attached to fructosylated phenolic compounds. The transfructosylation of epicatechin by P. graminis LS4 resulted in the most diversified products, with up to five fructosyl units transferred. In addition to the LS source, the acceptor specificity of LS towards phenolic compounds and their transfructosylation products were found to greatly depend on their chemical structure: the number of phenolic rings, the reactivity of hydroxyl groups and the presence of aliphatic chains or methoxy groups. Similarly, for carbohydrates, the transfructosylation yield was dependent on both the LS source and the acceptor type. The highest yield of fructosylated-trisaccharides was Erlose from the transfructosylation of maltose catalyzed by LS2, with production reaching 200 g/L. LS2 was more selective towards the transfructosylation of phenolic compounds and carbohydrates, while reactions catalyzed by LS1, LS3 and LS4 also produced fructooligosaccharides. This study shows the high potential for the application of LSs in the glycosylation of phenolic compounds and carbohydrates.
摘要：
这项研究表征了氧化葡糖杆菌（LS1）的左旋蔗糖酶（LSs）的受体特异性，纳氏弧菌（LS2），新香藻（LS3），和使用蔗糖作为果糖基供体并选择酚类化合物和碳水化合物作为受体的Paraburkholderiagraminis（LS4）。总的来说,V.natriegensLS2被证明是酚类化合物转果糖糖基化的最佳生物催化剂。多于一个果糖基单元可以连接到果糖糖基化的酚类化合物上。graminisLS4对表儿茶素的转果糖糖基化导致了最多样化的产品，转移了多达五个果糖基单位。除了LS源，发现LS对酚类化合物及其转果糖糖基化产物的受体特异性在很大程度上取决于它们的化学结构：酚环的数量，羟基的反应性和脂族链或甲氧基的存在。同样，对于碳水化合物，转果糖的产量取决于LS来源和受体类型。LS2催化的麦芽糖转果糖化产生的果糖糖基化三糖的产量最高，产量达到200g/L。LS2对酚类化合物和碳水化合物的转果糖糖基化更具选择性，而LS1、LS3和LS4催化的反应也产生低聚果糖。这项研究显示了LSs在酚类化合物和碳水化合物的糖基化中的应用潜力。
