Enhanced gastrointestinal stability and therapeutic efficacy of biofilm self-coated Bacillus amyloliquefaciens C-1 probiotic in ulcerative colitis

Abstract Given the rising global incidence of inflammatory bowel disease (IBD) and limited treatment options, probiotic efficacy is hindered by poor gastrointestinal survival. This study developed a self-coating biofilm technology to encapsulate the probiotic Bacillus amyloliquefaciens C-1 and yield cC-1. Biofilm-modified cC-1 exhibited a more negative zeta potential (-22.53 mV) compared to uncoated C-1 (-19.60 mV), representing a decrease of 2.93 mV decreased zeta potential, and it exhibited orders of magnitude higher survival than uncoated cells under simulated gastric acid (80.51% vs . 0.33%) and bile salt (84.32% vs . 1.64%). In DSS-induced colitis mice, oral administration of 10⁹ CFU cC-1 for 14 days significantly alleviated symptoms, reduced colon shortening and restored mucosal integrity. Mechanistically, cC-1 effectively downregulated pro-inflammatory cytokines (TNF- α , IL-1 β , IL-6 and IFN- γ ) in colon tissues; reshaped the diversity of gut microbiota by enriching beneficial Bacteroides ; restored linoleic acid and glycerophospholipid metabolism, and suppressed expression of NF- κ B signaling and cell adhesion molecule. Transcriptomic analysis confirmed that cC-1 reinstated host-microbe metabolic interactions with suppressed inflammatory pathways. This biofilm self-coating strategy substantially enhances probiotic gastrointestinal tolerance and exerts therapeutic effects through a multi-targeted mechanism (anti-inflammation, barrier repair, microbiota modulation, and metabolic reprogramming), offering a scalable and promising formulation for nutritional intervention in IBD.