Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 420111, Lobachevsky Str., 2/31, Kazan, Russia; Kazan National Research Technological University, 420015, Karl Marx Str., 68, Kazan, Russia; Kazan (Volga Region) Federal University, 420008, Kremlevskaya, 18, Kazan, Russia.
Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 420111, Lobachevsky Str., 2/31, Kazan, Russia; Kazan National Research Technological University, 420015, Karl Marx Str., 68, Kazan, Russia.
Int J Biol Macromol. 2024 Nov;281(Pt 1):136092. doi: 10.1016/j.ijbiomac.2024.136092. Epub 2024 Sep 28.
Microorganisms produce a wide variety of polysaccharides. Due to biosafety considerations, lactic acid bacteria (LAB) are popular producers of exopolysaccharides (EPS) for various applications. In this study, we analyzed the composition and properties of EPS produced by L. delbrueckii ssp. bulgaricus and LAB from clover silage (L. fermentum AG8, L. plantarum AG9) after growth on Man, Rogosa, and Sharpe broth (MRS) and with the addition of flaxseed mucilage (FSM) using chromatography, microscopy, and biochemical methods. We found that adding 0.4 % FSM does not drastically alter the medium's rheology but substantially increases EPS yield (by 3.1 to 3.8 times) and modifies the composition and macrostructure of EPS, as well as changes the spatial organization of LAB cells. The presence of FSM led to the production of xylose- and glucose-enriched EPS, which also contained varying proportions of fucose, rhamnose, arabinose, mannose, glycosamines, and uronic acids, depending on the strain. Most EPS had a low molecular weight (up to 32 kDa), except for EPS produced by L. fermentum AG8 in FSM-containing medium, which had molecular weight of 163 kDa. All EPS exhibited a porous microstructure and demonstrated scavenging capacity for OH- and DPPH-radicals, as well as high levels of α-glucosidase and lipase inhibitory activities, even at low concentrations (<1 g·L of EPS). These characteristics make them promising for use in functional food production and medicine.
微生物产生各种各样的多糖。由于生物安全方面的考虑，乳酸菌（LAB）是各种应用中生产胞外多糖（EPS）的热门生产者。在这项研究中，我们使用色谱、显微镜和生化方法分析了在 Man、Rogosa 和 Sharpe 肉汤（MRS）中生长并添加亚麻籽胶（FSM）后，由乳杆菌保加利亚亚种和来自三叶草青贮的 LAB（L. fermentum AG8、L. plantarum AG9）产生的 EPS 的组成和性质。我们发现，添加 0.4%的 FSM 不会显著改变培养基的流变性，但会大大增加 EPS 的产量（增加 3.1 到 3.8 倍），并改变 EPS 的组成和宏观结构，同时改变 LAB 细胞的空间组织。FSM 的存在导致了富含木糖和葡萄糖的 EPS 的产生，这些 EPS 还含有不同比例的岩藻糖、鼠李糖、阿拉伯糖、甘露糖、糖胺和糖醛酸，具体取决于菌株。大多数 EPS 的分子量较低（最高达 32 kDa），但在含有 FSM 的培养基中由 L. fermentum AG8 产生的 EPS 除外，其分子量为 163 kDa。所有 EPS 都表现出多孔的微观结构，并具有清除 OH-和 DPPH-自由基的能力，以及高水平的α-葡萄糖苷酶和脂肪酶抑制活性，即使在低浓度（<1 g·L 的 EPS）下也是如此。这些特性使它们有望用于功能性食品生产和医学。
