Recent advances in lactic acid bacteria-derived extracellular vesicles.

Abstract

Lactic acid bacteria (LAB) are globally recognized for their essential roles in food fermentation and impact on human health. Recent evidence identifies bacterial extracellular vesicles (EVs) as unique functional entities, serving as key mediators in microbe-host interactions. LAB-EV biogenesis is primarily driven by mechanisms that compromise cell-wall integrity, including prophage-encoded holin-endolysin systems and autolysin activity. EVs as nano-sized particles exert diverse beneficial effects by inhibiting pathogens, shaping microbiota composition, reinforcing the intestinal epithelial barrier, and modulating host immunity. Their ability to cross biological barriers and reach distal organs also implies systemic impacts. Consequently, LAB-EVs are emerging as a versatile platform for next-generation postbiotics and delivery systems, capable of protecting and transporting bioactive compounds. The interpretation of the effects conveyed by LAB-EVs requires critical considerations regarding mechanistic depth and cargo heterogeneity. A so-far overlooked factor is the influence of bacteriophage elements, which can influence both biogenesis pathways and host immune signatures. To successfully transition toward industrial and clinical applications, research must shift from observational studies to rigorous mechanistic evaluations and standardized production strategies, such as the use of prophage-cured strains or the development of artificial EV-mimics. This review synthesizes recent advances in LAB-EV biology and outlines the considerations necessary to harness these nano-couriers as valuable tools in modern biomedicine and food science.