Fucosylated oligosaccharides are interesting molecules due to their bioactive properties. In particular, their application as active ingredient in milk powders is attractive for dairy industries. The objective of this study was to characterize the glycosyl hydrolase family 29 α-fucosidase produced by Aspergillus niger and test its ability to transfucosylate lactose with a view towards potential industrial applications such as the valorization of the lactose side stream produced by dairy industry. In order to reduce costs and toxicity the use of free fucose instead of environmentally questionable fucose derivatives was studied. In contrast to earlier studies, a recombinantly produced A. niger α-fucosidase was utilized. Using pNP-fucose as substrate, the optimal pH for hydrolytic activity was determined to be 3.8. The optimal temperature for a 30-min reaction was 60 °C, and considering temperature stability, the optimal temperature for a 24-h reaction was defined as 45 °C For the same hydrolysis reaction, the kinetic values were calculated to be 0.385 mM for the K_M and 2.8 mmol/(mg*h) for the V_max. Transfucosylation of lactose occurred at high substrate concentrations when reaction time was elongated to several days. The structure of the product trisaccharide was defined as 1-fucosyllactose, where fucose is α-linked to the anomeric carbon of the β-glucose moiety of lactose. Furthermore, the enzyme was able to hydrolyze its own transfucosylation product and 2′-fucosyllactose but only poorly 3-fucosyllactose. As a conclusion, α-fucosidase from A. niger can transfucosylate lactose using free fucose as substrate producing a novel non-reducing 1-fucosyllactose.

中文翻译：

---

黑曲霉GH29家族α-岩藻糖苷酶的生产和表征以及新型的非还原性1-岩藻糖基乳糖的生产。

岩藻糖基化低聚糖由于其生物活性而成为令人感兴趣的分子。特别地，它们作为奶粉中的活性成分的应用对乳制品行业具有吸引力。这项研究的目的是表征黑曲霉产生的糖基水解酶家族29α-岩藻糖苷酶，并测试其转化岩藻糖基乳糖的能力，以寻求潜在的工业应用，例如乳制品工业生产的乳糖支流的增值。为了降低成本和毒性，研究了使用游离岩藻糖代替对环境有问题的岩藻糖衍生物的使用。与早期研究相反，重组生产的黑曲霉利用α-岩藻糖苷酶。以pNP-岩藻糖为底物，确定水解活性的最佳pH为3.8。30分钟反应的最佳温度为60°C，考虑到温度稳定性，将24小时反应的最佳温度定义为45°C。对于相同的水解反应，动力学值经计算为0.385 mM。V _max的K _M和2.8 mmol /（mg * h）。当反应时间延长到几天时，乳糖的岩藻糖基化在高底物浓度下发生。产物三糖的结构定义为1-岩藻糖半乳糖，其中岩藻糖与乳糖的β-葡萄糖部分的异头碳α连接。此外，该酶能够水解其自身的岩藻糖基化产物和2'-岩藻糖半乳糖，但仅水解较差的3-岩藻糖半乳糖。结论是，来自黑曲霉的α-岩藻糖苷酶可以使用游离岩藻糖为底物将乳糖转岩藻糖基化，从而产生新型的非还原性1-岩藻糖基乳糖。