Updated scheme for the classification of bacteriocins in gram-positive bacteria and a comprehensive overview for Lactobacillaceae

SUMMARYMany gram-positive bacteria, particularly those within the family Lactobacillaceae, possess significant biotechnological potential across food, feed, supplement, pharmaceutical, and agricultural sectors. Numerous species produce bacteriocins or ribosomally synthesized antimicrobial peptides, some of which undergo post-translational modifications that may confer a competitive advantage in complex microbial communities. These beneficial properties, along with their capacity to produce such bioactive molecules, make Lactobacillaceae a valuable microbial group with broad application potential. This review provides a comprehensive overview of bacteriocin classes within Lactobacillaceae, detailing their classification, mechanisms of action, and genetic organization. We propose a unified classification system, including an extension of existing classes and a standardized, source-based nomenclature for ribosomally produced and post-translationally modified peptides (RiPPs) and unmodified bacteriocins from gram-positive bacteria to enhance clarity and consistency. While proposed for Lactobacillaceae, our proposal fits within the broader scope of the field for the development of community standards in line with the scope of, for example, the "Minimum Information about a Biosynthetic Gene cluster" (MIBiG) database. We also systematically reviewed all reported bacteriocins within Lactobacillaceae, identifying 474 individual bacteriocins to date. Despite advances in genome and peptidome technologies, most remain only partially characterized. Notably, the majority of producing strains originate from food-related niches, highlighting the untapped potential of species from underexplored environments. Given the growing threat of antibiotic resistance and the demand for natural food preservatives, there is an urgent need to fully characterize these bioactive molecules and discover new ones from lesser-studied Lactobacillaceae species for future applications.