Insights into gut microbiota and metabolite profiles during in vitro fermentation of Volvaria volvacea polysaccharides: unraveling the central role of Bacteroides thetaiotaomicron

Volvaria volvacea polysaccharides (VVP) possess diverse bioactivities with promising applications in biomedicine and functional foods. This study investigated the metabolic fate of VVP in human gut microbiota and uncovered the pivotal role of Bacteroides thetaiotaomicron using in vitro fecal fermentation models. VVP selectively promoted B. thetaiotaomicron proliferation, establishing it as a central hub in microbial interaction networks. Metabolomic profiling revealed significant increases in short-chain fatty acids (SCFAs) and adenosine during VVP fermentation. KEGG pathway enrichment demonstrated activation of starch and sucrose metabolism and histidine biosynthesis, consistent with PICRUSt functional predictions. Network correlation and sole‑carbon source assays confirmed B. thetaiotaomicron as a key VVP degrader. These findings establish B. thetaiotaomicron as a dual-function mediator that orchestrates VVP bioconversion into bioactive metabolites and reshapes gut microenvironment. This mechanistic framework supports the development of VVP-based, microbiota-targeted interventions to enhance gut health.