Acetic Acid Bacteria: Metabolic Potential, Technological Applications and Emerging Probiotic Functions

Acetic acid bacteria (AAB, family Acetobacteraceae) are obligate aerobic microorganisms characterized by a highly efficient oxidative metabolism driven by membrane-bound dehydrogenases. Their ability to incompletely oxidize ethanol and various carbohydrates underlies the production of key food-related metabolites, including acetic acid, gluconic acids, and bacterial cellulose. This review summarizes current knowledge on AAB physiology, metabolic pathways, and ecological adaptations, with emphasis on their relevance to food biotechnology and value-added bioprocesses. AAB plays a central role in traditional and modern food fermentations, contributing to the production of vinegar, cocoa, coffee, kombucha, and other fermented beverages. Their metabolites influence food preservation, sensory attributes, and texture formation, supporting the development of clean-label and sustainable food products. In addition, AAB are increasingly applied in environmental biotechnology, including biodegradation and wastewater treatment, owing to their tolerance to acidic and oxidative stress conditions. Recent advances in metabolic and genetic engineering have enhanced the efficiency, robustness, and product specificity of industrial AAB strains, enabling improved production of organic acids, bacterial cellulose, and other high-value compounds. Emerging evidence also highlights the potential probiotic and postbiotic functions of selected AAB strains, including modulation of gut microbiota, production of bioactive metabolites, and support of intestinal barrier integrity, although these properties remain less explored than in lactic acid bacteria. Despite significant progress, challenges persist in strain standardization, genetic accessibility, and process optimization. Future research should focus on developing advanced engineering tools, improving large-scale fermentation strategies, and further elucidating the functional and health-related properties of AAB. Overall, AAB represents versatile microbial platforms with expanding applications in food science, biotechnology, and sustainable bioprocessing.