ORP-regulated natural accumulation of pyruvate in Actinobacillus succinogenes 130Z

Pyruvate, a pivotal metabolite in the glycolytic pathway, typically confronts substantial barriers to its natural accumulation within microbial cells. This study successfully facilitated the natural accumulation of pyruvate in Actinobacillus succinogenes 130Z by fine-tuning the oxidation-reduction potential (ORP) in the fermentation milieu. A mechanistic exploration revealed that the accumulation of pyruvate was optimized when ORP conditions favorably modulated pyruvate kinase activity and concurrently suppressed succinate dehydrogenase activity. By integrating the influence of metal ions on enzymatic functions with an innovative aluminum ion-mediated ORP control strategy, we achieved a pyruvate yield of 27.54 g/L over 20 hours, which constitutes an 89.54 % increase compared to the baseline. Additionally, the production rate of pyruvate reached 1.38 g/L·h. This investigation not only elucidates the metabolic underpinnings that facilitate the natural enrichment of glycolytic intermediates in Actinobacillus succinogenes 130Z but also lays a robust theoretical foundation for the industrial-scale fermentation of pyruvate. Moreover, the capability to efficiently and rapidly concentrate essential platform metabolites within the glycolytic pathway is of paramount significance, potentially propelling forward the research and synthesis of various downstream metabolic products.