Co-encapsulation of Lactiplantibacillus plantarum and Clostridium tyrobutyricum in gelatin-xylan microcapsules for high-yield butyric acid production: Preparation and in vitro assessment

Butyric acid, a key biomarker of intestinal health, can be efficiently synthesized through a synergistic fermentation system utilizing xylan as a substrate and a co-culture of Lactiplantibacillus plantarum and Clostridium tyrobutyricum . In this study, we developed a novel gelatin–xylan-based probiotic microcapsule delivery system to enhance probiotic stability and butyric acid production. The system was fabricated via Maillard reaction-mediated conjugation followed by spray drying. Physicochemical characterization confirmed that the microcapsules exhibited a uniform particle size distribution and stable surface charge properties. Importantly, gelatin–xylan encapsulation significantly improved the storage stability and survival of L. plantarum and C. tyrobutyricum , maintaining a viable bacterial count of 7 log CFU/mL after 4 h of simulated gastrointestinal digestion. Furthermore, in vitro fecal fermentation showed that the co-encapsulation system produced 0.92 g/L butyric acid, which was 6.57-fold higher than that of the non-encapsulated group. Microbial community analysis further revealed that the formulation selectively enriched beneficial genera, including Lactobacillus , Clostridium , Bifidobacterium , and Sutterella . Collectively, these findings highlight the dual functionality of the engineered microcapsules in enhancing butyric acid production and modulating gut microbial composition. • Co-culture and co-encapsulation of L. plantarum and C. tyrobutyricum significantly increase butyric acid production. • Probiotics are encapsulated using spray-dried microcapsules derived from gelatin–xylan Maillard conjugates. • Gelatin–xylan encapsulation markedly enhances the survival and storage stability of L. plantarum and C. tyrobutyricum . • Co-encapsulated probiotics significantly increase butyrate yield and enrich beneficial gut flora during in vitro fermentation.