Marine-derived lactic acid bacteria fermentation enhances the bioactivity of Neopyropia haitanensis by improving intestinal homeostasis.

This study investigated the functional fermentation of Neopyropia haitanensis using marine-derived lactic acid bacteria (LAB), aiming to develop effective strategies to improve the bioactivity and functionality of seaweed-based foods. Fifteen LAB strains were isolated from marine sources, among which three strains, namely Pediococcus pentosaceus HYZ2-1, Limosilactobacillus reuteri HYS1-1, and Ligilactobacillus salivarius HYD1-1 with superior fermentation performance, were selected. In vitro cellular assays indicated that the fermented products exhibited antioxidant, anti-inflammatory, and intestinal barrier-enhancing effects. Furthermore, in colitis mice, the fermented products alleviated symptoms such as weight loss, hematochezia, and colon shortening, and significantly reduced serum interleukin (IL)-6 levels while increasing IL-10 levels, compared with the unfermented samples. Colon tissues showed decreased malondialdehyde and increased superoxide dismutase and catalase activities. The gene expressions of tight junctions and mucin 2 were upregulated. Metabolomic analysis revealed consistent upregulation of specific bioactive metabolites across all fermented groups, and these metabolites were strongly correlated with the observed improvements in antioxidant capacity, immune modulation, and intestinal barrier integrity. Overall, this study demonstrates the functional advantages of marine-derived LAB in enhancing the bioactivity of N. haitanensis, providing new insights into the development of seaweed-based functional foods, especially for gut health.