一株芽孢杆菌胞外多糖的分离纯化及其抗氧化性测定

Isolation and Purification of Exopolysaccharide from the Fermentation Broth of Bacillus sp. and Its Antioxidant Effect

摘要:

基于实验室从新疆罗布泊沙漠筛选到一株芽孢杆菌, 研究了该菌胞外多糖的分离纯化工艺及其抗氧化性质。发酵液经离心, 抽滤等预处理后, 使用Sevag试剂除蛋白, 并以无水乙醇作提取溶剂, 通过正交实验确定最佳提取条件为: pH为7.0, 温度为4°C, 时间为1.5 h, 料液比为1:4。粗多糖溶解后上活性炭柱(1.5 cm ′ 24 cm), 用蒸馏水、60%乙醇及95%乙醇洗脱, 分离得到主要部分, 再经Sephadex G-100凝胶柱, 用0.2 mol/L的NaCl溶液洗脱, 硫酸苯酚法和考马斯亮蓝

Abstract:

Based on the Bacillus sp., isolated from Lop Nur Desert, the technology of separation and purification and the antioxidant effect were studied. After centrifugation and vacuum filtration, the deproteinization of supernatant was operated with Sevag reagent. The crude exopolysaccharide (EPS) was obtained by precipitation with ethanol. The optimum conditions for the isolation were as follow: pH 7.0, temperature 4°C, time 1.5 h, and material to ethanol ratio 1: 4. Dissolved in water, the crude EPS was fractional separated on activated carbon column (1.5 cm × 24 cm), eluted with distilled water, 60% ethanol, 95% ethanol, and the main fraction was collected. Then the EPS was purified on Sephadex G-100 gel column, eluted with NaCl (0.2 mol/L). Fractions (4 mL, each) were also combined according to total sugar by phenol-sulfuric acid method and protein content was determined by Coomassie brilliant blue. The results showed that EPS was relatively homogeneous glycoprotein. The data of antioxidation in vitro showed that the EPS had a high an-tioxidant activity, which could quench hydroxyl radical, superoxide radical and had antilipid peroxidation activity. All of these indicated that EPS was a good natural antioxidant.