Enhancing the Biocontrol Potential of Bacillus amyloliquefaciens by Hydrogel Encapsulation for Combating Intestinal Pathogens

This study investigates a Bacillus amyloliquefaciens strain isolated from pearl millet to determine its suitability as a probiotic and to enhance its delivery through sodium alginate encapsulation. The isolate was examined for key probiotic characteristics, including acid and phenol tolerance, cell surface hydrophobicity, auto-aggregation ability, NaCl tolerance, and hemolytic activity. To improve stability and survival, the cells were encapsulated in sodium alginate hydrogel. The encapsulation process was verified through FTIR, which revealed the functional groups characteristic of alginate, and XRD analysis confirmed an amorphous structure with slight crystallinity, indicating efficient bead formation. GC–MS profiling identified a diverse set of 65 metabolites, with 1,2-Benzenedicarboxylic acid diethyl ester being the most prominent. Encapsulated cells showed significantly improved survival in acidic, gastrointestinal-like conditions, demonstrating the protective effect of the hydrogel. The cell-free supernatant also exhibited notable antibacterial activity, forming inhibition zones against Escherichia coli and Shigella. Overall, the results highlight B. amyloliquefaciens as a strong probiotic candidate. Encapsulation in sodium alginate enhanced stability, maintained metabolic activity, and offered controlled release, underscoring its potential for future food and pharmaceutical applications.