Dynamic Metabolic Regulation Enhances 3-Hydroxypropionic Acid Production in Escherichia coli

Abstract

3-Hydroxypropionic acid (3-HP) is a key intermediate for producing sustainable materials such as biodegradable plastics and acrylic derivatives. While microbial biosynthesis of 3-HP has been widely explored, production efficiency is often hindered by challenges in cofactor availability and metabolic competition for precursors. In particular, maintaining a sufficient supply of NADPH and managing malonyl-CoA partitioning between biosynthesis pathways are critical for enabling high-level 3-HP production. Conventional strategies based on static metabolic engineering frequently result in unbalanced flux, limited adaptability, and reduced yield under variable physiological conditions. In this study, we evaluated a metabolite-responsive regulatory approach for coordinating metabolic flux in a microbial host. By introducing a feedback circuit responsive to 3-HP accumulation, expression of enzymes related to cofactor regeneration and precursor metabolism was modulated in response to the metabolic state of the cell. This regulatory system functions without external inducers and enables context-sensitive redistribution of metabolic flux toward 3-HP synthesis. It facilitates dynamic regulation of redox balance and precursor supply, contributing to enhanced pathway efficiency and reduced metabolic burden. When applied to engineered strains of E. coli, this regulatory strategy resulted in substantially elevated 3-HP levels under batch fermentation conditions compared to strains relying solely on fixed expression systems. These results suggest that context-aware metabolic control strategies can provide meaningful improvements in microbial production systems without requiring manual pathway tuning. More broadly, the approach demonstrated here offers a generalizable framework for modulating intracellular fluxes in response to pathway intermediates, with potential applications in the production of other high-value biochemicals. By integrating feedback regulation and metabolic engineering, this study highlights the value of dynamic control mechanisms in the development of next-generation microbial cell factories.