Bacteriocins from Limosilactobacillus and Ligilactobacillus: ecological logic, mechanistic diversity, and translational potential in the post-Lactobacillus taxonomy.

Bacteriocins are ribosomally synthesized antimicrobial peptides that contribute to microbial competition, niche establishment, and community structure. The 2020 taxonomic reorganization of the former broad Lactobacillus genus provides a useful framework for reinterpreting bacteriocin diversity in lineage-specific ecological contexts. This review focuses on bacteriocins produced by species now assigned to Limosilactobacillus and Ligilactobacillus, two host- and food-associated genera that include several reported bacteriocin producers. These genera were selected because they contain bacteriocins with diverse structural features, including cyclic peptides, class IIa and IIb peptides, class IId peptides, defensin-like peptides, and larger proteinaceous bacteriocins, and because many producer strains originate from competitive ecological niches such as the gastrointestinal tract, oral cavity, vagina, milk, poultry, livestock, and fermented foods. We synthesize evidence on bacteriocin biosynthetic gene clusters, molecular diversity, antimicrobial mechanisms, ecological functions, physicochemical stability, and translational potential. This review also distinguishes bacteriocin-specific evidence from effects attributable to bacteriocin-producing strains, particularly for immunomodulation, co-aggregation, pathogen exclusion, and microbiota modulation. Finally, we address how comparative genomics, structured genome mining and artificial intelligence-aided prediction can speed bacteriocin discovery, emphasizing the necessity of experimental validation, standardized activity assays, safety evaluation and scalable production. This study gives a systematic framework to understand the bacteriocins of Limosilactobacillus and Ligilactobacillus in the post-Lactobacillus era by integrating taxonomy, ecology, mechanism and translational evidence.