Liu Yixi, Wu Yazhen, Ji Hangyan, Li Xiaoxiao, Jin Zhengyu, Svensson Birte, Bai Yuxiang
State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China; Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, Wuxi, Jiangsu 214122, China; International Joint Research Laboratory for Starch Related Enzyme at Jiangnan University, Wuxi, Jiangsu 214122, China.
International Joint Research Laboratory for Starch Related Enzyme at Jiangnan University, Wuxi, Jiangsu 214122, China; Enzyme and Protein Chemistry, Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
Carbohydr Polym. 2023 Jun 15;310:120716. doi: 10.1016/j.carbpol.2023.120716. Epub 2023 Feb 19.
Isomalto/malto-polysaccharides (IMMPs) derived from malto-oligosaccharides such as maltoheptaose (G7) are elongated non-branched gluco-oligosaccharides produced by 4,6-α-glucanotransferase (GtfB). However, G7 is expensive and cumbersome to produce commercially. In this study, a cost-effective enzymatic process for IMMPs synthesis is developed that utilizes the combined action of cyclodextrinase from Palaeococcus pacificus (PpCD) and GtfB-ΔN from Limosilactobacillus reuteri 121 to convert β-cyclodextrin into IMMPs with a maximum yield (16.19 %, w/w). The purified IMMPs synthesized by simultaneous or sequential treatments, designated as IMMP-Sim and IMMP-Seq, possess relatively high contents of α-(1 → 6) glucosidic linkages. By controlling the release of G7 and smaller malto-oligosaccharides by PpCD, IMMP-Seq was obtained of DP varying from 12.9 to 29.5. Enzymatic fingerprinting revealed different linkage-type distribution of α-(1 → 6) linked segments with α-(1 → 4) segments embedded at the reducing end and middle part. The proportion of α-(1 → 6) segments containing the non-reducing end was 56.76 % for IMMP-Sim but 28.98 % for IMMP-Seq. Addition of G3 or G4 as specific acceptors resulted in IMMPs exhibiting low polydispersity. This procedure can be applied as a novel bioprocess that does not require costy high-purity malto-oligosaccharides and with control of the average DP of IMMPs by adjusting the substrate composition.
由麦芽寡糖（如麦芽七糖，G7）衍生而来的异麦芽/麦芽多糖（IMMPs）是由4,6-α-葡聚糖转移酶（GtfB）产生的伸长型无分支葡糖寡糖。然而，G7的商业生产昂贵且繁琐。在本研究中，开发了一种具有成本效益的IMMPs合成酶法工艺，该工艺利用来自太平洋古球菌的环糊精酶（PpCD）和来自罗伊氏乳杆菌121的GtfB-ΔN的联合作用，将β-环糊精转化为IMMPs，最大产率为16.19%（w/w）。通过同时或顺序处理合成的纯化IMMPs，分别命名为IMMP-Sim和IMMP-Seq，具有相对较高含量的α-(1→6)糖苷键。通过控制PpCD对G7和较小麦芽寡糖的释放，获得了聚合度在12.9至29.5之间变化的IMMP-Seq。酶指纹图谱显示α-(1→6)连接片段与嵌入还原端和中间部分的α-(1→4)片段具有不同的连接类型分布。对于IMMP-Sim，含有非还原端的α-(1→6)片段比例为56.76%，而对于IMMP-Seq为28.98%。添加G3或G4作为特定受体导致IMMPs表现出低多分散性。该方法可作为一种新型生物工艺应用，该工艺不需要昂贵的高纯度麦芽寡糖，并且通过调整底物组成来控制IMMPs的平均聚合度。
