Engineered Bacillus subtilis for high-yield nattokinase production and therapeutic potential in obesity management.

backgroundNattokinase (NK), a serine protease renowned for its thrombolytic activity, holds immense promise for addressing cardiovascular diseases and metabolic disorders. However, its clinical and industrial translation has been severely hampered by low yields in conventional expression systems, which rely on inefficient solid-state fermentation or suboptimal recombinant platforms. Meanwhile, the global burden of obesity and its associated cardiovascular diseases remain prominent. To this end, implementing a fed-batch fermentation strategy for precise nutrient control is a critical approach to breaking through yield bottlenecks and achieving high-density NK production. Meanwhile, introducing in vivo animal model studies enables a more systematic evaluation of the actual therapeutic efficacy and mechanisms of recombinant NK in improving lipid metabolism and alleviating cardiovascular complications.

resultsFirst, we engineered a robust recombinant Bacillus subtilis strain (T3) by harnessing a strong constitutive promoter (Pspovg) and a dual-reporter system (NK-eGFP fusion), enabling real-time monitoring of protein expression. This platform achieved a groundbreaking NK activity of 1.18 × 10

conclusionThese findings collectively establish NK as a multifunctional enzyme with applications extending beyond its well-known thrombolytic properties to include metabolic syndrome management. The study provides both a theoretical foundation and practical methodology for large-scale NK production while expanding the therapeutic potential in obesity management. By integrating advances in genetic engineering, fermentation technology, and physiological evaluation, this work represents a significant step forward in harnessing microbial enzymes for therapeutic purposes.