Bacterial Extracellular Vesicles in Biotechnology: Current Challenges and Strategies for Production Enhancement

Bacterial extracellular vesicles (BEVs) are nanosized (10–400 nm), membrane-enclosed particles naturally secreted by both Gram-negative and Gram-positive bacteria. Initially characterized as virulence factors in pathogenic species, BEVs are now recognized as multifunctional entities with significant biotechnological potential. Their cargo—comprising proteins, lipids, nucleic acids, and metabolites—enables diverse biological activities, including immune modulation, epithelial barrier protection, stress tolerance, and intercellular communication. Recent studies have highlighted BEVs from biotechnologically relevant bacteria—such as plant growth-promoting rhizobacteria, lactic acid bacteria, bifidobacteria, cyanobacteria, bacilli, and streptomycetes—for their different roles in biological and ecological interactions. These properties underpin emerging applications in health, agriculture, and bioprocessing, including next-generation postbiotics, vaccine platforms, drug and RNA delivery systems, and novel plant biostimulants. However, major challenges persist, particularly low production yields, variability in cargo composition, and scalability. Addressing these limitations requires a deeper understanding of vesiculation mechanisms and the development of process-oriented strategies for BEV recovery and purification. This review synthesizes recent advances in genetic analysis, physiological modulation, physicochemical stimuli, and bioprocess optimization aimed at enhancing BEV production and stabilizing cargo profiles, providing a comprehensive overview of approaches to unlock the full potential of BEVs as versatile biotechnological tools.