Simulated Digestion and Fecal Fermentation Behaviors of Levan and Its Impacts on the Gut Microbiota

Abstract

Levan is a microbial fructan widely explored in various fields owing to its excellent physical and biochemical properties. However, little is known about its digestion and fermentation characteristics in vitro. This study evaluated the potential prebiotic properties of levan obtained by enzymatic synthesis. Scanning electron microscopy, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy showed that the primary structures of levan remained stable after saliva–gastrointestinal digestion. The microtopography, molecular weight, and functional group of levan were seriously damaged during fecal fermentation. Moreover, the total short-chain fatty acid levels increased significantly, especially for propionic acid, butyric acid, and valeric acid. The 16S rDNA sequencing showed that levan mainly increased the abundance of Firmicutes; in genus levels, certain beneficial bacteria such as Megasphaera and Megamonas genera were remarkably promoted, and the proliferation of harmful genera was inhibited (such as Cedecea and Klebsiella). Overall, this study provided new insights into the potential probiotic mechanism of levan.

Preparation, Structural Analysis, and Intestinal Probiotic Properties of a Novel Oligosaccharide from Enzymatic Degradation of Huangshui Polysaccharide

“…A higher percentage of Escherichia-Shigella in the HSO and Inulin groups species may be due to its utilization of low-molecular-weight carbon sources to maintain its growth . Therefore, the results showed that the dominant microbiota of the HSO group was different from that of the Inulin group, indicating that they have different probiotic properties . In summary, HSO showed potential probiotic properties by regulating the composition of the gut microbiota, which promoted the growth of beneficial bacteria, while inhibiting the colonization of harmful bacteria.…”

“…16 Therefore, the results showed that the dominant microbiota of the HSO group was different from that of the Inulin group, indicating that they have different probiotic properties. 25 In summary, HSO showed potential probiotic properties by regulating the composition of the gut microbiota, which promoted the growth of beneficial bacteria, while inhibiting the colonization of harmful bacteria. In addition, the heatmap in Figure 4E showed the relative abundance of the top 30 bacterial species at the genus level in the Blank, HSO, and Inulin groups.…”

“…The intestinal microbiota is an intricate microbial ecosystem that is extensively involved in a broad range of physiological functions of the organism, and its architecture and arrangement reflect the mutualistic coevolution between microbes and the host. 25 The advancements in 16S rRNA gene sequencing technology in recent years have made the study of intestinal diseases and the exploration of the gut's relationship with the organism's health more feasible using gut microbes. 26 Prior to fermentation by intestinal microbiota, in vitro simulated digestion of HSO under saliva, gastric, and small intestinal conditions was conducted.…”

Bifidobacterium bifidum Ameliorates DSS-Induced Colitis in Mice by Regulating Microbial Metabolome and Targeting Gut Microbiota

“…47 Levan has been reported to effectively regulate the gut microbiota balance, and increase the abundance of beneficial bacteria like Megasphaera and Megamonas genera while inhibiting the proliferation of harmful bacteria such as Cedecea and Klebsiella. 48 Correlation analyses between metabolites and gut microbiota revealed distinct associations (Figure S7). Specifically, Lactobacillus exhibited a significantly positive correlation with estriol and isomaltose, but showed a significantly negative correlation with N-acetyl-D-mannosamine.…”

Macro insights into the shared and distinct regulations of dietary polysaccharides on gut microbiota and their roles in obesity

“…Similar to other DP, FLPs from various sources significantly reduce the abundance of Firmicutes and the F/B ratio (Healey et al., 2018), which represents the main mechanism through which DP exert their health effects by regulating gut microbiota. However, some studies have also indicated that FLPs significantly increase the abundance of Firmicutes and even suppress the abundance of Bacteroides , resulting in a higher F/B ratio (Dewulf et al., 2013; Xu et al., 2023). This effect may be attributed to the pronounced proliferation of specific beneficial bacteria within the Firmicutes phylum induced by FLPs.…”