The Metabolic Reprogramming Mechanism by Pueraria Lobata Fermentation Enhances Saccharomyces cerevisiae Reducing-Sugar-Releasing Activity and Polypeptide Synthesis.

Pueraria lobata is a widely distributed traditional Chinese medicinal herb, and its active constituents have potential value in food, pharmaceutical, cosmetic, and industrial fermentation applications. In this study, P. lobata was used as the substrate and Saccharomyces cerevisiae as the fermenting organism. Response surface methodology was employed to optimize fermentation conditions using peptide concentration in the broth as the target response. The effects of P. lobata on S. cerevisiae were evaluated by measuring yeast colony counts, protease activity, and sodium alginate-based reducing-sugar-releasing activity. Transcriptomic profiling combined with GO/KEGG enrichment analyses and qRT-PCR validation was further used to analyze gene expression differences in S. cerevisiae at 5, 24, and 48 h. The optimal fermentation conditions were 71 h, 22.41 °C, and a solid-to-liquid ratio of 1:20, under which the peptide concentration reached 32.37 mg/mL. Relative to conventional yeast medium, protease activity and reducing-sugar-releasing activity in the P. lobata fermentation broth increased by 2.37-fold and 10.1-fold, respectively. Supplementation with 10% P. lobata most effectively promoted S. cerevisiae proliferation, resulting in the highest colony count of 6.8 × 10