Biosynthesis of Melanin with Engineered Probiotics for Oral Treatment of Ulcerative Colitis

imaging revealed increased colonization efficiency and retention time of EcN-Mel in inflamed intestinal segments. EcN-Mel enhances beneficial bacteria of the Lactobacillus genus while decreasing harmful members of the Proteobacteria genus, promoting gut microbiota homeostasis, and alleviating colitis. EcN-Mel alleviated intestinal mucosal damage through combined actions, including gut microbiota modulation, oxidative stress reversal, cytokine regulation, and barrier restoration. Our findings confirm the safety, feasibility, and effectiveness of EcN-Mel for UC treatment.