本论文从大连地区海产品消化腺中筛选产胞外多糖(EPS)的乳杆菌属菌株，并研究其所产EPS的功能特性，选出一株目标菌，对其EPS分离纯化，测定纯化后各多糖组分的相对分子量。获得EPS产量相对较高的菌株经16S rRNA序列测定鉴定为Lactobacillus plantarum subsp.plantarum-4，Lactobacillus plantarum-12，Lactobacillus plantarumsubsp. plantarum-49；对3株植物乳杆菌及其EPS进行清除DPPH自由基的测定，Lactobacillus plantarum-12的EPS浓度为0.5 mg/mL时，清除率为48.82±3.88%，显著高于另外2株菌（p<0.05）；测定植物乳杆菌的EPS抑制E. coli ATCC25922在HT-29细胞上的粘附效果，Lactobacillus plantarum-12的EPS浓度为0.2 mg/mL时，抑制率为78.23%±2.46%，显著高于另外两株菌（p<0.05）；Lactobacillus plantarum-12的EPS可显著抑制E?coli ATCC25922刺激HT-29细胞产生IL-8（p<0.05）。Lactobacillus plantarum-12的EPS经DEAE-Sepharose Fast Flow离子交换柱、Sepharose CL-6B凝胶柱和Sephacryl HR S200凝胶柱层析分离得到两组分，测定两组分的相对分子质量分别为8.5×104 u和7.4×104 u。

Exopolysaccharide (EPS)-producing Lactobacillus strains were screened from the digestive glands of seafood from the Dalian area, and the functional properties of the produced EPSs were studied. One target strain was selected, the corresponding EPS was isolated and purified, and the relative molecular weights of all purified polysaccharide components were measured. Strains with relatively high EPS-producing ability were identified as Lactobacillus plantarum subsp. plantarum-4, Lactobacillus plantarum-12, and Lactobacillus plantarum subsp. plantarum-49. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging abilities of the three Lactobacillus plantarum strains and their EPSs were measured. When the EPS produced by Lactobacillus plantarum-12 was at a concentration of 0.5 mg/mL, the DPPH free radical scavenging rate was 48.82±3.88%, significantly higher than those of other two strains (p<0.05). The effect of EPS produced by Lactobacillus plantarum strains on the inhibition of the adhesion of Escherichia coli ATCC 25922 to HT-29 cells was measured. When the EPS produced by Lactobacillus plantarum-12 was at a concentration of 0.2 mg/ml, the inhibitory rate was 78.23%±2.46%, significantly higher than those of other two strains (p<0.05). The EPS produced by Lactobacillus plantarum-12 could significantly inhibit IL-8 production by HT-29 cells stimulated by E. coli ATCC 25922 (p<0.05). The crude EPS produced by Lactobacillus plantarum-12 was purified by DEAE-Sepharose anion-exchange, Sepharose CL-6B, and Sephacryl HR S200 chromatography columns; two fractions were obtained, and their relative molecular weights were 8.5×104 u and 7.4×104 u.

本课题由国家十二五科技支撑计划项目（2013BAD18B09）；国家自然科学基金项目（31571813）；国家海洋食品工程技术研究中心项目（2012FU125X03）；辽宁省自然科学基金项目（2014026018）资助