In Vitro Fecal Fermentation Properties Of Pulse Cell Wall Polysaccharides And The Gut Microbiota Regulation Induced By Different Enterotype Fecal Inocula

The relationship between the gut microbiota and human health is increasingly recognized.Studies have shown that the intake of dietary fiber can regulate the composition and metabolic function of the microbial community and thus play an important role in human health.Pulse is a rich source of dietary fiber,mainly non-starch polysaccharides from the cell wall.Previous studies have found that stratifying individuals according to human enterotype may help predict the diet response.In this study,cell wall polysaccharides were extracted and purified from cotyledons of pulse.The fermentation characteristics and effects on the gut microbiota of pulse cell wall were explored through in vitro fermentation of three volunteers mixed inocula.Afterwards,the in vitro fecal fermentation by individual Prevotella and Bacteroides enterotype inocula were performed to further investigate the in vitro fermentation profiles and microbiota changes of pea cell wall polysaccharides.The results of this study provided a basis for the prebiotic effect of cell wall polysaccharides and personalized nutrition interventions.The research was conducted as the following two aspects:The in vitro fermentation characteristics and effect on gut microbiota of pulse cell wall polysaccharides.The cotyledon cell walls of nine representative varieties of pulses in my country,including smooth pea,chickpea,red kidney bean,runner bean,large white kidney bean,white hyacinth bean,broad bean,adzuki bean and mung bean,were extracted and purified,and their monosaccharide composition was determined.The in vitro fermentation with mixed inocula of three volunteers was performed to determine the gas production,short-chain fatty acids(SCFAs)and microbiota responses.The results showed that the pulse cell wall polysaccharides were mainly composed of arabinose(25.7?39.3%),glucose(12.0?20.5%),galactose(5.5?9.7%),xylose(4.6?9.1%),rhamnose(0.9?1.7%),fucose(0.5?1.8%),and uronic acid(15.2?21.7%).The contents of arabinose,glucose and galactose in all pulse cell wall are significantly different,while the contents of fucose(except for red kidney beans)and rhamnose are not significantly different.Compared to FOS,nine pulse cell walls showed a slow and continuous fermentation rate,especially at the initial 4 h.Mung beans produced the highest gas production about 6 m L during 4?8 h of fermentation,while runner bean showed the highest gas production about 6 m L during 8?12 h.At the end of fermentation,all pulse cell wall showed high concentrations of acetate about 50 m M and 20?25 m M propionate(except for runner bean),while the production of butyrate was different,and the butyrate production of broad bean cell wall was the lowest,about 7 m M,runner bean is the highest,about 14 m M.Based on 16 S r RNA gene sequencing,it was found that cell wall fermentation promoted the growth of Prevotella and related ASV,and the fermentation of pulse cell wall also significantly altered the structure of the microbial community,but no significant difference observed between nine pulse,indicating that the regulation of different pulse cell wall fermentation on the microbial community was mainly reflected in the abundance of microbiota composition.Redundancy analysis showed that SCFAs are positively correlated with the pulse cell wall order distribution,and have the greatest correlation with acetate.Among the key amplicon sequence variants,ASV23655,ASV353,ASV10566 and ASV11284 Prevotella copri are positively associated with all pulse cell wall distribution(except for runner bean).In vitro fecal fermentation profiles and microbiota responses of pea cell wall polysaccharides by individual Prevotella and Bacteroides enterotype inocula.The gas production,monosaccharide degradation profiles,short chain fatty acid production and microbiota responses of pea cell wall(PCW)polysaccharide in vitro fermentation by individual Prevotella and Bacteroides enterotype inocula were determined.The results showed that the Prevotella and Bacteroides enterotype microbiota had a significant effect on gas production,monosaccharide degradation profiles,SCFAs production,and microbiota changes after PCW fermentation.The fermentation rate of Prevotella was faster than Bacteroides,and caused more gas production(3 m L)at the end of fermentation.As for monosaccharide degradation and utilization,the arabinose and uronic acid were degraded faster than glucose during the fermentation period,and Prevotella also utilized the monosaccharides faster than Bacteroides.During the whole fermentation period of PCW,Prevotella produced more SCFAs,especially propionate and butyrate than Bacteroides.At the end of PCW fermentation,the propionate production of Prevotella and Bacteroides was about 30 m M and 24 m M,and butyrate production was about 17 m M and 10 m M,respectively.Prevotella and Bacteroides enterotype promoted the abundance of Prevotella and Bacteroides respectively after PCW fermentation,resulting in different fermentation characteristics.In PCA analysis,Prevotella and their related fermented samples clustered with the initial microbiota but separated with Bacteroides and their related fermented samples.