Novel α-glucooligosaccharides were synthesized by the acceptor reaction of Leuconostoc citreum SK24.002 glucansucrase with maltose and sucrose. The impact of synthesis conditions, including the ratio of sucrose to maltose and the substrate concentration, on the formation of α-glucooligosaccharides was evaluated. Under the optimized experimental conditions, the yield of a mixture of α-glucooligosaccharides with DP 3-5 reached approximately 56.4% with a concentration of 170.7 mg mL-1. Each of these α-glucooligosaccharides was purified, and the structures were assigned as follows: α-D-Glcp-(1,6)-α-D-Glcp-(1,4)-D-Glcp (DP3), α-D-Glcp-(1,3)-α-D-Glcp-(1,6)-α-D-Glcp-(1,4)-D-Glcp (DP4), and α-D-Glcp-(1,6)-α-D-Glcp-(1,3)-α-D-Glcp-(1,6)-α-D-Glcp-(1,4)-D-Glcp (DP5), respectively. For these three structurally different oligosaccharides, the fermentation selectivity by fecal bacteria was determined in anaerobic batch culture. Fructooligosaccharide (FOS) was used as a positive prebiotic control. Similar to FOS, all three α-glucooligosaccharides selectively stimulated the proliferation of Bifidobacteria and Lactobacilli compared with the control. DP3 exhibited the strongest prebiotic ability to increase the Bifidobacterium and Lactobacillus population, whereas DP5 produced the most short-chain fatty acids. In addition, DP4 produced the highest butyrate concentration and resulted in the lowest acetate : propionate ratio. These results suggested that the enzymatically synthesized α-glucooligosaccharides were potential prebiotics, underlining correlations between the structural features of oligosaccharides and their impact on the metabolism of fecal microbiota.

中文翻译：

---

利用微生物葡糖苷酶合成潜在的益生元α-葡萄糖寡糖及其体外粪便发酵。

通过柑桔类隐球菌SK24.002葡聚糖蔗糖酶与麦芽糖和蔗糖的受体反应合成了新型α-葡萄糖寡糖。评价了合成条件，包括蔗糖与麦芽糖的比例和底物浓度，对α-葡萄糖寡糖形成的影响。在优化的实验条件下，α-葡萄糖寡糖与DP 3-5的混合物的收率达到约56.4％，浓度为170.7 mg mL-1。这些α-葡萄糖寡糖均经过纯化，其结构分配如下：α-D-Glcp-（1,6）-α-D-Glcp-（1,4）-D-Glcp（DP3），α- D-Glcp-（1,3）-α-D-Glcp-（1,6）-α-D-Glcp-（1,4）-D-Glcp（DP4）和α-D-Glcp-（1 ，6）-α-D-Glcp-（1,3）-α-D-Glcp-（1,6）-α-D-Glcp-（1,4）-D-Glcp（DP5）。对于这三种结构上不同的寡糖，在厌氧分批培养中测定粪便细菌的发酵选择性。低聚果糖（FOS）用作益生元阳性对照。与FOS相似，与对照组相比，所有三种α-葡萄糖寡糖均选择性刺激双歧杆菌和乳杆菌的增殖。DP3表现出最强的益生元增加双歧杆菌和乳杆菌种群的能力，而DP5产生最多的短链脂肪酸。另外，DP4产生最高的丁酸酯浓度，并导致最低的乙酸酯：丙酸酯比率。这些结果表明，酶促合成的α-葡萄糖寡糖是潜在的益生元，突显了寡糖的结构特征与其对粪便微生物群代谢的影响之间的相关性。