Glycosidic Linkage of Rare and New-to-nature Disaccharides Reshapes Gut Microbiota in Vitro

The impact of glycosidic linkage of seven rare and new-to-nature disaccharides on gut bacteria was assessed in vitro. The community shift of the inocula from four donors in response to 1 % (w/v) disaccharide supplemen-tation was captured by sequencing the 16S rRNA gene. A significant loss of bacterial alpha diversity, short lag time, low pH, and high total short-chain fatty acid displayed a faster fermentation of trehalose(Glc-alpha 1,1 alpha-Glc) and fibrulose(fructan, DP2-10). Bacteroides reduced in relative abundance under disaccharide supplementation suggesting a loss in complex carbohydrates metabolizing capacity. Fibrulose and L-arabinose glucoside(Glc-alpha 1,3-L-Ara) significantly stimulated bifidobacteria but was suppressed with trehalose, ribose glucoside(Glc-alpha 1,2-Rib), and 4 '-epitrehalose(Glc-alpha 1,1 alpha-Gal) supplementation. Albeit insignificant, bifidobacteria increased with 4 '-epi-kojibiose(Glc-alpha 1,2-Gal), nigerose(Glc-alpha 1,3-Glc), and kojibiose(Glc-alpha 1,2-Glc). Prior conditioning of inoculum in kojibiose medium profoundly induced bifidobacteria by 44 % and 55 % upon reinoculation into kojibiose and fibrulose-supplemented media respectively. This study has demonstrated the importance of the disaccharide structure-function relationship in driving the gut bacterial community.