人肠道来源霍氏肠杆菌4-2-1的分离及其对枸杞多糖的发酵作用

Isolation of Enterobacter hohensis 4-2-1 from Human Intestine and Its Fermentation Effect on Lycium Barbarum Polysaccharide

为了阐明肠道细菌在枸杞多糖吸收过程中的作用,本论文主要针对1株从人体肠道粪便中分离到的细菌进行研究,并将该菌株用于枸杞多糖发酵,并以发酵中细菌总数、pH、多糖含量、还原糖含量和分子量为指标反映发酵特性,初步阐明了枸杞多糖的消化和吸收。结果表明,通过形态学观察和分子生物学鉴定,该菌株为肠道单菌霍氏肠杆菌4-2-1(Enterobacter Hoechnii),为革兰氏阴性菌,且该菌在发酵到12 h细菌总数达到最大,发酵后,培养基的pH由7.98变为7.75、多糖含量由682μg/mL变为205.7μg/mL、还原糖含量由225μg/mL变为91.32μg/mL,分子量由8.02 kDa变为3.44 kDa。结果发现,枸杞多糖在经过霍氏肠杆菌发酵后,多糖含量下降为原来的30.2%左右,还原糖含量下降为40.6%左右,分子量下降为42.9%,说明肠道菌能发酵利用枸杞多糖,研究为进一步研究多糖和肠道菌的相互作用提供依据。

In order to investigate the role of intestinal bacteria in the absorption of Lycium barbarum polysaccharides(LBP),a strain of bacteria was isolated from human intestinal feces,and the strain was applied in the fermentation of LBP.The total number of bacteria,pH,polysaccharide content,reducing sugar content and molecular weight in the fermentation were measured and analysed to initially elucidate the digestion and absorption of LBP.The results showed that the strain was Enterobacter hormaechei through morphological and molecular biology identification,marked 4-2-1,which was a Gram-negative bacterium,and that it reached its maximum total bacterial count at 12 h.After fermentation,the pH of the medium changed from 7.98 to 7.75,the polysaccharide content changed from 682μg/mL to 205.7μg/mL,the reducing sugar content changed from 225μg/mL to 91.32μg/mL,and the molecular weight changed from 8.02 to 3.44 kDa,the content of LBP decreased to about 30.2%,the content of reducing sugar decreased to about 40.6% and the molecular weight decreased to 42.9%.It indicated that the intestinal bacteria could ferment and utilize LBP,which would provide a basis for further study on the interaction between LBP and intestinal bacteria.