Developing Robust Probiotic Consortia: A Methodological Optimization Approach.

Developing effective probiotic consortia requires a comprehensive understanding of strain interactions. While traditional methods focus on direct interactions of the participating microbes, the role of microbial metabolites remains largely unexplored. Present study introduces a novel approach of evaluating the impact of strains as well as their secondary metabolites on compatibility during co-culture by assessing the antagonistic and synergistic attributes for multi-strain probiotic formulation. Assessment of antagonistic activity by spot method indicated suppressive nature of PIG1FD and PIG1IR on other strain's growth, hence not appropriate for consortia formulation. Findings of synergistic attribute demonstrated growth promoting role of cell supernatants from isolates PIG6IR and PIG5CI significantly, as it accelerated the entry of all other isolates into the log phase by 5-6 h and 0-2 h, respectively. By employing this methodology, we identified PIG5CI and PIG6IR (isolates identified as Bacillus spizizenii BAB 7915 and Bacillus subtilis BAB 7918 by 16S RNA sequencing method) as promising candidates for consortium formation due to their ability to enhance the growth of other strains through metabolite production. By attempting to elucidate the microbial interactions and metabolite-mediated effects, this research contributes to a more comprehensive understanding of probiotic consortia dynamics and offers valuable insights for future translational studies.