School of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou 730050, China; School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, China.
School of Energy and Power Engineering, Lanzhou University of Technology, Lanzhou 730050, China.
Int J Biol Macromol. 2019 Jul 15;133:172-183. doi: 10.1016/j.ijbiomac.2019.03.246. Epub 2019 Apr 2.
The yield, composition, structure and biofunction of microorganism exopolysaccharide (EPS) depended on their genetics and metabolic pathways. An EPS-producing endophytic fungus was isolated from Angelica sinensis planted in Dingxi, Gansu, China, and identified as Alternaria tenuissima F1. The production optimization, purification and characterization of the purified EPS from A. tenuissima F1 and the in-vitro antioxidant potentials was investigated. Results showed the optimal medium composition were 8% mannose, 2% yeast extract, 0.04% MgSO·7HO, 0.005% Vc, and the optimal cultivation conditions were set at initial pH 7.0, culture temperature 30 °C, inoculum size of 3%, 180 r/min for 5 d. The EPS purified by ion exchange column chromatography and gel chromatography was a non-reducing sugar and glycoprotein with pyranoid ring by Fourier transform infrared spectroscopy (FT-IR) analysis, displayed a porous network structure by scanning electron microscope (SEM) observation and exhibited a high thermal stability with the degradation temperature of 303.9 °C by thermogravimetric analysis (TG/DSC). Molecular weight of the purified EPS was 3.246 × 10 g/mol, and EPS was composed of d-galacturonic acid, rhamnose, d-mannose, glucose, and d-galactose in ratio of 0.45:3.02:3.25:1.0:0.95. The EPS exhibited strong scavenging activity and may be a new source of natural antioxidant.
微生物胞外多糖（EPS）的产量、组成、结构和生物功能取决于其遗传和代谢途径。从中国甘肃定西种植的当归中分离到一株产胞外多糖的内生真菌，鉴定为细极链格孢菌 F1。研究了从细极链格孢菌 F1 中提取和纯化 EPS 的生产优化、纯化和表征以及体外抗氧化潜力。结果表明，最佳培养基组成为 8%甘露糖、2%酵母提取物、0.04%MgSO·7HO、0.005%Vc，最佳培养条件为初始 pH 7.0、培养温度 30°C、接种量 3%、180r/min 培养 5d。经离子交换柱层析和凝胶层析纯化的 EPS 为非还原糖和糖蛋白，吡喃环通过傅里叶变换红外光谱（FT-IR）分析，通过扫描电子显微镜（SEM）观察显示出多孔网络结构，并通过热重分析（TG/DSC）显示出高的热稳定性，其降解温度为 303.9°C。纯化的 EPS 的分子量为 3.246×10 g/mol，由半乳糖醛酸、鼠李糖、甘露糖、葡萄糖和半乳糖组成，比例为 0.45:3.02:3.25:1.0:0.95。EPS 具有很强的清除活性，可能是天然抗氧化剂的新来源。
