Abstract

Functional constipation is a prevalent gastrointestinal disorder associated with gut microbiota dysbiosis. Probiotics have emerged as a promising strategy to restore microbial balance, particularly strains capable of degrading dietary fibres like pectin. In this study, two indigenous pectin-degrading strains, Lactiplantibacillus plantarum PD-14 and Lactiplantibacillus pentosus PD-16, which were isolated from fermented tofu, were used to facilitate the decomposition of dietary fiber in the intestinal tract, and to modulate intestinal microbiota composition and metabolic activity. Whole-genome sequencing revealed the presence of pectate lyase 3 family pectate lyase genes in both strains, establishing their intrinsic capacity for dietary fibre utilization. In a loperamide-induced constipation murine model, both strains exhibited a favorable safety profile and alleviated constipation symptoms. Notably, the two strains exhibited distinct regulatory profiles. L . plantarum PD-14 increased fecal short-chain fatty acids, particularly acetic acid and propionic acid, accompanied by an enrichment of Bifidobacterium . In contrast, L. pentosus PD-16 shortened whole-gut transit time and reduced the abundance of constipation-associated taxa, such as Faecalibaculum . Unlike the drug PEG-4000, both probiotic strains successfully changed the gut microbiota. These findings demonstrated that indigenous, pectin-degrading microbes alleviate constipation through strain-specific mechanisms, supporting the development of regionally adapted probiotics for precise health management.