PDF(Pubmed)
Abstract：
Six lactic acid bacteria (LAB) isolated from Algerian sheep\'s milk, traditional butter, date palm sap and barley, which produce dextran, mannitol, oligosaccharides and vitamin B2 have been characterized. They were identified as Leuconostoc mesenteroides (A4X, Z36P, B12 and O9) and Liquorilactobacillus mali (BR201 and FR123). Their exopolysaccharides synthesized from sucrose by dextransucrase (Dsr) were characterized as dextrans with (1,6)-D-glucopyranose units in the main backbone and branched at positions O-4, O-2 and/or O-3, with D-glucopyranose units in the side chain. A4X was the best dextran producer (4.5 g/L), while the other strains synthesized 2.1-2.7 g/L. Zymograms revealed that L. mali strains have a single Dsr with a molecular weight (Mw) of ~ 145 kDa, while the Lc. mesenteroides possess one or two enzymes with 170-211 kDa Mw. As far as we know, this is the first detection of L. mali Dsr. Analysis of metabolic fluxes from sucrose revealed that the six LAB produced mannitol (~ 12 g/L). The co-addition of maltose-sucrose resulted in the production of panose (up to 37.53 mM), an oligosaccharide known for its prebiotic effect. A4X, Z36P and B12 showed dextranase hydrolytic enzymatic activity and were able to produce another trisaccharide, maltotriose, which is the first instance of a dextranase activity encoded by Lc. mesenteroides strains. Furthermore, B12 and O9 grew in the absence of riboflavin (vitamin B2) and synthesized this vitamin, in a defined medium at the level of ~ 220 μg/L. Therefore, these LAB, especially Lc. mesenteroides B12, are good candidates for the development of new fermented food biofortified with functional compounds.
摘要：
从阿尔及利亚羊奶中分离出六种乳酸菌，传统黄油,椰枣汁和大麦,生产葡聚糖，甘露醇,寡糖和维生素B2已被表征。它们被鉴定为肠系膜明串珠菌(A4X，Z36P,B12和O9）和苹果酒杆菌（BR201和FR123）。通过葡聚糖蔗糖酶（Dsr）从蔗糖合成的胞外多糖的特征为葡聚糖，在主主链上具有（1,6）-D-吡喃葡萄糖单元，并在O-4，O-2和/或O-3位分支，在侧链上具有D-吡喃葡萄糖单元。A4X是最好的葡聚糖生产者（4.5g/L），而其他菌株合成2.1-2.7g/L。酶谱图显示，马利乳杆菌菌株具有分子量（Mw）为〜145kDa的单个Dsr，而Lc。中肠动物具有一种或两种具有170-211kDaMw的酶。据我们所知,这是L.maliDsr的首次检测。对来自蔗糖的代谢通量的分析表明,六个LAB产生甘露醇(〜12g/L)。麦芽糖-蔗糖的共同添加导致潘糖的产生（高达37.53mM），一种以益生元效应而闻名的低聚糖。A4X,Z36P和B12表现出葡聚糖酶水解酶活性，能够产生另一种三糖，麦芽三糖,这是由Lc编码的葡聚糖酶活性的第一个实例。肠系膜菌株。此外，B12和O9在没有核黄素（维生素B2）的情况下生长并合成了这种维生素，在确定的培养基中，水平为〜220μg/L。因此,这些实验室,尤其是Lc。中肠杆菌B12是开发新的功能性化合物生物强化的发酵食品的良好候选者。
