Prebiotic activity comparison of eight oligosaccharides: selection of a potential synbiotic containing konjac manna-oligosaccharides and <i>Bifidobacterium animalis</i> BB-12

Various types of non-digestible oligosaccharides (NDOs) have attracted tremendous interest due to their healthy functions in regulating intestinal microbiota. Whereas the specificity of different NDOs towards certain intestinal bacterial species remains unclear. In this study, konjac manna-oligosaccharides (KMOS) were selected from eight NDOs through <i>in vitro</i> faecal batch fermentation. KMOS accelerated increase of recognised probiotics (<i>Bifidobacterium</i> spp. and <i>Akkermansia</i> spp.) and achieved the highest productions of lactic acid and total short-chain fatty acids (42.0 mM). β-Mannosidase and β-glucosidase played important role in the utilisation of KMOS, and mannobiose and glucosyl-mannobiose were preferentially consumed by faecal microbiota. In pure culture, the utilisation of KMOS was tested with nine <i>Bifidobacterium</i> strains. Amongst, KMOS increased the cell density of <i>B. animalis</i> BB-12 by 3.5 folds and improved its adhesion ability to Caco-2 cell by 3.1 folds, suggesting that KMOS and <i>B. animalis</i> BB-12 may be developed as a potential synbiotic combination.