发酵乳杆菌产胞外多糖的益生元样作用研究

PREBIOTIC PROPERTIES OF EXOPOLYSACCHARIDES PRODUCED BY LACTOBACILLUS FERMENTUM

目的探讨发酵乳杆菌胞外多糖(exopolysaccharide,EPS)的益生元样作用,为开发功能性食品提供实验依据。方法发酵乳杆菌在MRS培养液中培养48h后用冰乙醇提取培养液上清中的胞外多糖经膜透析和柱子分离纯化后,在模拟胃酸pH(2.0、2.5、3.0),胆汁(0.5%、1%、2%胆盐)环境下观察EPS对18株从人肠道或粪便中分离的益生菌株生长和菌落形态的影响。结果发酵乳杆菌产EPS可选择性的影响肠道益生菌生长,在模拟胃肠道环境下0.2%的EPS可显著促进Lactobacillus reuteri ATCC23272的生长。另外,培养基中添加EPS能够更好的保持菌落形态。结论发酵乳杆菌产EPS可在模拟胃肠道环境中促进益生菌生长,Lactobacillus reuteri ATCC23272以及发酵乳杆菌产EPS的综合利用可增强人肠道健康,在新型功能性食品开发和加工过程中可用作为合生元。

Objective Investigate the prebiotic properities of exopolysaccharides(EPS) produced by Lactobacillus fermentum, to provide experimental evidence for developing functional food. Methods The EPS, extracted from 48 h culture broth supernatant of Lactobacillus fermentum by using ice-cold ethanol, was purified by membrane dialysis and column separation. The effects of 0.2% EPS on the growth and colony morphology of 18 probiotic strains, which were isolated from human intestines or feces, were tested under in vitro artificial gastrointestinal conditions, including low pH(2.0,2.5,3.0) and bile salt(0.5%. 1%, 2%) contained condition. Results Under our experimental conditions, EPS produced by Lactobacillus fermentum selectively influenced the probiotic strains growth and morphology. Especially, it stimulated the growth of Lactobacillus reuteri ATCC 23272, protected strain morphology against the gastric low pH condition, when compared with non-EPS contained medium. Conclusion EPS produced by Lactobaclllus fermentum can beneficially improve the probiotic strains cell growth, and can be used as a symbiotic in the developing and processing of new functional foods.