Background: Food fermentation is among the oldest food-processing technologies, historically valued for preservation, safety, and sensory quality, and increasingly recognized as a pillar of sustainable food systems. Beneficial microorganisms transform agricultural raw materials into safer, more nutritious, and more resource-efficient products, while offering a route for valorizing agri-food by-products within a circular bioeconomy.
Objective: This review synthesizes current knowledge on microbial fermentation technologies, their contribution to nutritional and functional food enhancement, and their industrial and sustainability implications, while identifying research gaps limiting scale-up and standardization.
Methods: A structured narrative review was conducted using peer-reviewed literature retrieved from PubMed, Scopus, Web of Science, ScienceDirect, and Google Scholar, focusing on studies published within the last five to seven years, supplemented by foundational classical works. Evidence was organized around microbial technologies, nutritional mechanisms, industrial applications, and sustainability outcomes.
Results: Lactic acid bacteria, yeasts, filamentous fungi, acetic acid bacteria, and Bacillus species drive diverse biochemical transformations—proteolysis, phytate degradation, vitamin biosynthesis, and phenolic bioconversion—that enhance digestibility, micronutrient bioavailability, and bioactive-compound content. Modern approaches, including precision and controlled fermentation, mixed-culture systems, and bioreactor-based processing, improve reproducibility and enable agricultural by-product valorization into food, feed, and functional ingredients.
Conclusion: Fermentation offers substantial, evidence-supported potential to improve nutritional quality and sustainability across agricultural and industrial food systems, though realizing this potential at scale requires improved process standardization, contamination control, regulatory clarity, and integration of omics- and digital-monitoring–based process optimization.