<i>Lactobacillus delbrueckii</i> : A Functional Powerhouse in Dairy Fermentation and Emerging Probiotic Applications

<i>Lactobacillus delbrueckii</i> is a key lactic acid bacterium (LAB) widely used in dairy fermentation, particularly in the production of yogurt, cheese, and kefir. Its metabolic activities-such as efficient lactose utilization, rapid acidification, and high proteolytic activity-make it an indispensable starter culture in the dairy industry. Beyond its technological advantages, <i>L. delbrueckii</i> contributes significantly to human health through the production of bioactive peptides (BAPs), extracellular polysaccharides (EPS), and other functional metabolites with antioxidant, anti-inflammatory, and immunomodulatory effects. Recent studies have also highlighted its role in gut health, cholesterol reduction, and potential anti-cancer activity, underscoring its value as a probiotic. This review provides a comprehensive overview of the taxonomy, metabolism, and health-promoting properties of <i>L. delbrueckii</i> while also exploring its potential applications in precision fermentation and the development of functional foods. The insights discussed herein position <i>L. delbrueckii</i> as a promising candidate for next-generation probiotic dairy innovations.