In vitro fermentation characteristics and interaction of neutral and acidic polysaccharides from Lycii fructus on human gut microbiota

In this study, the microbial fermentation characteristics and effects of neutral and acidic Lycii fructus polysaccharides (LFPs) on gut microbial composition were investigated using pure cultures of selected probiotic strains and mixed cultures of human fecal microflora in vitro. The results revealed that LFPs could significantly promote the growth of probiotics, with a faster proliferation rate in the early stages of fermentation. When LFPs were degraded and utilized by the gut microbiota, neutral arabinogalactans were more easily fermented, while acidic pectin polysaccharides exhibited a higher degree of anti-fermentation. LFPs were selectively modulated by microbiota; acidic polysaccharides promoted the growth of potentially beneficial bacteria, such as Lachnospira and Bacteroides vulgatus, while neutral polysaccharides significantly improved the relative abundances of Bifidobacterium longum and Bifidobacterium pseudocatenulatum. In summary, the results revealed that different types of LFPs regulate the gut microbiota in a structure-dependent manner, with uronic acid play a key role in selective regulation. This study aimed to better understand the fermentation characteristics and saccharide preferences of gut microbes for LFP structures and provide a theoretical basis for the relationship between the chemical structural and probiotic effects of LFPs.