假肠膜明串珠菌HDL-3胞外多糖的分离纯化及结构性质分析

赵丹; 曹慧莹; 孙梦; 于连升; 杜仁鹏

doi:10.13386/j.issn1002-0306.2022020092

假肠膜明串珠菌HDL-3胞外多糖的分离纯化及结构性质分析

Isolation, Purification and Structural Properties Analysis of Exopolysaccharide from Leuconostoc pseudointestinalis HDL-3

摘要

摘要: 从东北自然酸菜发酵液中分离筛选出一株高产胞外多糖（exopolysaccharides，EPS）的乳酸菌，通过16S rDNA分析将该菌株鉴定为假肠膜明串珠菌（Leuconostoc pseudomesenteroides）HDL-3。利用该菌株进行发酵产EPS、分离纯化EPS，并解析EPS的结构和性质。结果表明，EPS是由α-(1,6)糖苷键连接而成的线性葡聚糖，分子量为1.581×10⁶ Da。EPS呈现表面光滑、有光泽、紧凑的片状非晶体结构。溶解率和持水率分别为98.63%±1.03%和401.30%±4.92%。此外，该EPS表现出非牛顿流体的剪切稀释特征，粘度与浓度呈正相关、与温度和pH呈负相关，不仅对大豆油、葵花籽油和苯具有较强的乳化能力，还对DPPH和ABTS自由基具有良好的清除能力。

Abstract: A strain of lactic acid bacteria (LAB) with high production of exopolysaccharides (EPS) was isolated and screened from the fermentation broth of natural sauerkraut in Northeast China. The strain was identified as Leuconostoc pseudomesenteroides HDL-3 by 16S rDNA. This strain was used to produce EPS by fermentation. EPS was isolated and purified, and the structure and properties of EPS were analyzed. The results showed that the EPS was a linear glucan linked by α-(1, 6) glycosidic bonds. The molecular weight was 1.581×10⁶ Da. The EPS presents a smooth, shiny and compact sheet-like amorphous structure. The solubility, water-holding capacity were 98.63%±1.03% and 401.30%±4.92%, respectively. In addition, the EPS showed the shear dilution characteristics of non-Newtonian fluid. The viscosity was positively correlated with concentration and negatively correlated with temperature and pH. It not only had strong emulsifying ability for soybean oil, sunflower seed oil and benzene, but also had good scavenging ability for DPPH and ABTS.