State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200030, China.
Int J Biol Macromol. 2019 May 1;128:710-717. doi: 10.1016/j.ijbiomac.2018.12.245. Epub 2018 Dec 27.
In this study exopolysaccharide (EPS) of Enterococcus faecium WEFA23 from healthy infant's feces was yielded as high as 130 mg/L by fermentation. By purification the EPS was further fractioned into A23-1, A23-2, A23-3 and A23-4 on HiTrap Q HP and Superdex G-200 column. As the major purified fractions, A23-2 and A23-4 were analyzed for the preliminary structures and investigated for the biological properties in vitro. The molecular weight of A23-2 and A23-4 was 2.50 × 10 Da and 3.23 × 10 Da, respectively. A23-2 was composed of mannose, glucose and galactose with a ratio of 1.38:1.00:1.42, while A23-4 consisted of only mannose. The antioxidant ability of A23-2 was significantly higher than that of A23-4, as proved by scavenging test of DPPH radical, hydroxyl radical and superoxide radical. Both A23-2 and A23-4 exhibited strong inhibition against the adhesion of L. monocytogenes CMCC54007 on HT-29 cells no matter for the styles of competition, displacement and exclusion. Notably, for exclusion they had a maximal inhibition rate of 89.85 ± 0.46% and 90.81 ± 2.29%, respectively, at 200 μg/mL.
在这项研究中，通过发酵，从健康婴儿粪便中分离出的屎肠球菌 WEFA23 的胞外多糖 (EPS) 产量高达 130mg/L。通过纯化，EPS 进一步在 HiTrap Q HP 和 Superdex G-200 柱上分为 A23-1、A23-2、A23-3 和 A23-4 四个部分。作为主要的纯化部分，对 A23-2 和 A23-4 进行了初步结构分析，并在体外研究了它们的生物学特性。A23-2 和 A23-4 的分子量分别为 2.50×10 Da 和 3.23×10 Da。A23-2 由甘露糖、葡萄糖和半乳糖组成，摩尔比为 1.38:1.00:1.42，而 A23-4 仅由甘露糖组成。A23-2 的抗氧化能力明显高于 A23-4，这一点通过 DPPH 自由基、羟基自由基和超氧自由基清除试验得到了证明。A23-2 和 A23-4 都能强烈抑制单核细胞增生李斯特菌 CMCC54007 在 HT-29 细胞上的黏附，无论是竞争、置换还是排除方式。值得注意的是，对于排除方式，它们在 200μg/mL 时的最大抑制率分别为 89.85±0.46%和 90.81±2.29%。
