Search

Alginate (Alg) has a long history as a food ingredient in East Asia. However, the human gut microbes responsible for the degradation of alginate and its derivatives have not been fully understood yet. Here, we report that alginate and the low molecular polymer derivatives of mannuronic acid oligosaccharides (MO) and guluronic acid oligosaccharides (GO) can be completely degraded and utilized at various rates by fecal microbiota obtained from six Chinese individuals. However, the derivative of propylene glycol alginate sodium sulfate (PSS) was not hydrolyzed. The bacteria having a pronounced ability to degrade Alg, MO and GO were isolated from human fecal samples and were identified as Bacteroides ovatus , Bacteroides xylanisolvens , and Bacteroides thetaiotaomicron . Alg, MO and GO can increase the production level of short chain fatty acids (SCFA), but GO generates the highest level of SCFA. Our data suggest that alginate and its derivatives could be degraded by specific bacteria in the human gut, providing the basis for the impacts of alginate and its derivates as special food additives on human health. [ABSTRACT FROM AUTHOR]

Heparin and its derivative are commonly used as injectable anticoagulants in clinical procedures, but possess poor oral bioavailability. To explore the role of gut microbiota in the poor oral effect of heparin, the degradation profiles of heparin on six human gut microbiota were investigated. The heparin-degradation ability varied significantly among individuals. Furthermore, two strains of heparin-degrading bacteria, Bacteroides ovatus A2 and Bacteroides cellulosilyticus B19, were isolated from the gut microbiota of different individuals and the degradation products of the isolates were profiled. The ΔUA2S-GlcNS6S was the major end product with almost no desulfation. 3- O -sulfo group-containing tetrasaccharides were detected, which indicated that the antithrombin binding site was broken and this explained the lost anticoagulant activity of heparin. Collectively, the present study assessed the degradation profiles of heparin by human gut microbiota and provided references for the development of oral administration of heparin from a gut microbiota perspective. • The heparin-degradation ability varied significantly among individuals. • B. ovatus and B. cellulosilyticus isolated from human fecal could degrade heparin. • The ΔUA2S-GlcNS6S was the major end degradation product in all isolates. • The products of 3- O -sulfo group-containing tetrasacchardes were detected. • Several breakdown products explained the destroyed anticoagulant activity of heparin. [ABSTRACT FROM AUTHOR]

B. ovatus is a member of the human gut microbiota with a broad capability to degrade complex glycans. Here we show that B. ovatus degrades plant polysaccharides in a preferential order, and that glycan structural complexity plays a role in determining the prioritisation of polysaccharide usage. • Bacteroides ovatus has a broad capability to degrade complex glycans. • B. ovatus degrades plant glycans in a preferential order. • Glycan structural complexity plays a role in determining prioritisation of glycan usage. [ABSTRACT FROM AUTHOR]