Bioproduction of 3‑Hydroxypropionic Acid by\nEnhancing the Precursor Supply with a Hybrid Pathway and Cofactor\nRegeneration

3-Hydroxypropionic\nacid (3-HP) is one of the 12 valuable platform\nchemicals with versatile applications in the chemical, food, and cosmetic\nindustries. However, the biosynthesis of 3-HP faces challenges due\nto the lack of robust chassis and the high costs associated with the\nfermentation process. To address these challenges, we made efforts\nto augment the robustness of 3-HP-producing chassis by exploiting\nmetabolic regulation, controlling carbon flux, balancing cofactor\ngeneration, and optimizing fermentation conditions. First, the malonyl-CoA\n(MCA) pathway was recruited and rebalanced in Escherichia\ncoli. Subsequently, a hybrid pathway integrating the\nEmbden–Meyerhof–Parnas pathway with the nonoxidative\nglycolysis pathway was systematically modulated to enhance carbon\nflux to the MCA pathway, followed by fine-tuning NADPH regeneration.\nThen, by optimizing the fermentation conditions, 3-HP production was\nsignificantly improved, reaching 6.8 g/L. Finally, in a fed-batch\nexperiment, the final chassis produced 42.8 g/L 3-HP, corresponding\nto a 0.4 mol/mol yield and 0.6 g/(L·h) productivity.