利用低聚半乳糖双歧杆菌的筛选及益生特性研究

Studies on Screening and Probiotic Characterization of Bifidobacteria with the Ability to Utilize Galacto-oligogalactosaccharides

短链低聚半乳糖(SC-GOS)是双歧杆菌的有效增殖因子。本试验从婴儿粪便样品中筛选得到7株高效利用SC-GOS的双歧杆菌,经16S r DNA鉴定,它们为1株为长双歧杆菌婴儿亚种BI_Y46,2株为两歧双歧杆菌(BB_Y22、BB_S7),2株假小链双歧杆菌(BP_Y43、BP_YA)以及2株长双歧杆菌(BL_S34、BL_H26)。以婴儿双歧杆菌M63和婴儿双歧杆菌ATCC15697为对照,观察菌株形态并分析益生特性,初步筛选出具有应用潜力的益生菌株。结果表明,BI_Y46形态特殊,分叉状有菌毛;BB_Y22、BP_Y43的胞外多糖产量超过0.45 mg/mL;BL_H26菌体表面蛋白含量较高,为0.74 mg/mL,BB_Y22、BB_S7含量在0.35~0.45 mg/mL范围;同时BP_Y43、BB_Y22具有较强的表面疏水性和自聚集能力;在模拟胃液中及胆盐存在下,BB_Y22、BI_Y46对胆盐和胃液的刺激显示出较强的耐受性。抑菌试验显示BI_Y46、BB_S7上清液对大肠杆菌ATCC 25922的抑菌效果较强。结论:长双歧杆菌婴儿亚种BI_Y46、两歧双歧杆菌BB_Y22以及假小链双歧杆菌BP_Y43具有较好的益生潜力,为开发含有低聚半乳糖和双歧杆菌的产品提供一定参考。

Short chain-galactooligosaccharides(SC-GOS)is an effective proliferation factor of Bifidobacteria.Seven strains of Bifidobacteria with high utilization of SC-GOS were screened from infant fecal samples,the result of 16S r DNA identification was that one was Bifidobacterium longum subsp.infantis BI_Y46,2 B.pseudocatenulatum(BP_Y43,BP_YA),2 B.bifidum(BB_Y22,BB_S7)and 2 strains of B.longum(BL_S34,BL_H26).Compared with B.infantis M63 and B.infantis ATCC 15697,the morphology of the strains was observed and the probiotic characteristics were analyzed.Thus,the probiotics with application potential were screened.The results showed that BI_Y46 had special morphology with bifurcated fimbriae,and the exopolysaccharide yield of BB_Y22 and BP_Y43 was higher than 0.45 mg/m L.The surface protein content of BL_H26 was(0.74±0.07)mg/m L,the content of BB_S7 and BB_Y22 was between 0.35-0.45mg/m L.Whereas,BP_Y43 and BB_Y22 had strong surface hydrophobicity and self-aggregation ability.BB_Y22 and BI_Y46 showed strong tolerance to the stimulation of bile salt and gastric juice.The supernatant of BI_Y46 and BB_S7had strong inhibiting effect on Escherichia coli ATCC 25922.In summary,B.infantis BI_Y46,B.bifidum BB_Y22 and B.pseudocatenulatum BP_Y43 had good probiotic potential and provide some reference for the development of products containing galactoseoligosaccharides and Bifidobacterium.