School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, PR China.
School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, PR China.
Int J Biol Macromol. 2018 Jun;112:1208-1216. doi: 10.1016/j.ijbiomac.2018.02.068. Epub 2018 Feb 14.
Response surface methodology (RSM) was used to optimize the fermentation condition of exopolysaccharide (EPS) producing strain Leuconostoc mesenteroides DRP105. Result showed that the optimum condition was sucrose 86.83g/L, tryptone 15.47g/L, initial pH7.18 and maximum yield was 53.79±0.78g/L in 36h fermentation. Chain conformation was characterized by Congo red test, β-elimination and circular dichroism (CD), which indicated that the EPS was O-linkage and exhibited random coil structure in aqueous solution. CD results concluded hydrogen-bond interaction and chirality might be connected with concentration. Purified EPS has a higher degradation temperature of 279.42°C, suggesting high thermal stability of the EPS. The absolute value of zeta potential and particle size were enhanced with increasing concentration. Crude EPS and its purified fraction were found to have moderate DPPH, hydroxyl, superoxide anion radicals scavenging activities and reducing power. This study provided a high yield EPS with unique characteristics for industrial applications.
响应面法（RSM）用于优化发酵条件产胞外多糖（EPS）的肠膜明串珠菌 DRP105 菌株。结果表明，最适条件为蔗糖 86.83g/L，胰蛋白胨 15.47g/L，初始 pH7.18，最大产量为 36h 发酵 53.79±0.78g/L。刚果红试验、β-消除和圆二色性（CD）对链构象进行了表征，表明 EPS 是 O-连接的，在水溶液中呈现无规卷曲结构。CD 结果表明氢键相互作用和手性可能与浓度有关。纯化的 EPS 具有较高的降解温度 279.42°C，表明 EPS 具有较高的热稳定性。随着浓度的增加，zeta 电位和粒径的绝对值增大。粗 EPS 及其纯化部分对 DPPH、羟基、超氧阴离子自由基有一定的清除作用，具有还原能力。本研究为工业应用提供了一种具有独特特性的高产 EPS。
