Qiqihar Medical University, Qiqihar 161000, China.
Qiqihar Medical University, Qiqihar 161000, China.
Int J Biol Macromol. 2020 Oct 15;161:1181-1188. doi: 10.1016/j.ijbiomac.2020.06.140. Epub 2020 Jun 17.
An exopolysaccharide (EPS)-producing bacterial PFY-147 was separated from Hiqiher vineyard soil and determined as Bacillus megaterium by 16S rDNA analysis and morphological. The PFY-147-EPS was purified by gel-filtration chromatography. The average molecular weight (Mw) of purified EPS was 1.878 × 10 Da. The total carbohydrate contents, uronic acid and sulfated group content in PFY-147-EPS were found to be 90.37 ± 1.48%, 7.24 ± 0.36% and 2.39 ± 0.36%, respectively. The PFY-147-EPS was found to be a levan containing a backbone of 2,6-substituted β-fructoses by high performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR) and Fourier transform infrared (FT-IR) spectroscopy. The atomic force microscopy (AFM) presented that the levan formed pointed or thorny structural in aqueous solution. Scanning electron microscopy (SEM) of the levan showed compact and nonuniform block sizes morphology. Moreover, the levan exhibited higher thermal stability with a degradation temperature of 265.63 °C in DSC analysis. The levan possessed strong 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, Superoxide anion (O) radical, hydroxyl (OH) radical and and2,20-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS) scavenging activities and strong metal ion chelating activity. The WHC and WSI of levan were 231.29 ± 3.76% and 97.34 ± 1.72%, respectively. These might have implications in food and medicine, as well as in pharmaceutical industries.
从和奇河葡萄酒庄土壤中分离到一株产胞外多糖（EPS）的细菌 PFY-147，经 16S rDNA 分析和形态学鉴定为巨大芽孢杆菌。采用凝胶过滤色谱法对 PFY-147-EPS 进行纯化，其平均分子量（Mw）为 1.878×10 Da。PFY-147-EPS 的总糖含量、糖醛酸和硫酸根含量分别为 90.37±1.48%、7.24±0.36%和 2.39±0.36%。高效液相色谱（HPLC）、核磁共振（NMR）和傅里叶变换红外（FT-IR）光谱分析表明，PFY-147-EPS 是一种以 2,6-取代β-果糖为骨架的低聚果糖。原子力显微镜（AFM）表明，低聚果糖在水溶液中形成尖或刺状结构。低聚果糖的扫描电子显微镜（SEM）显示其形貌为致密且不均匀的块状。此外，低聚果糖在差示扫描量热分析（DSC）中具有较高的热稳定性，其降解温度为 265.63°C。低聚果糖具有较强的 1,1-二苯基-2-苦基肼（DPPH）自由基、超氧阴离子（O ）自由基、羟基（OH ）自由基和 2,20-偶氮-双（3-乙基苯并噻唑啉-6-磺酸）自由基阳离子（ABTS）清除活性以及较强的金属离子螯合活性。低聚果糖的水合能力（WHC）和水分保持能力（WSI）分别为 231.29±3.76%和 97.34±1.72%。这些特性可能使其在食品、医药和制药等行业具有潜在应用价值。
