Dynamic Pathway Regulation Guided by Product-Sensing Biosensor for Enhanced Bioproduction

Abstract

Maximizing microbial biosynthesis of platform chemicals requires tight control of intracellular metabolic fluxes. However, most conventional gene expression systems rely on constant gene expression or external inducers, which hinder dynamic responses to real-time cellular metabolic changes. In this study, we established an autonomously regulated expression system that responds directly to intracellular product accumulation. By incorporating a product-sensing biosensor, we enabled real-time modulation of critical metabolic pathways related to cofactor recycling and precursor utilization. When product accumulated to a certain threshold, the system activates pathways that enhance reducing equivalent supply and in parallel, represses competing metabolic pathways. This phase-dependent strategy aligns metabolic activity with the production stage, redirecting flux toward product formation without compromising cellular fitness during early growth. The engineered strain exhibited a five-fold improvement in production titer relative to the non-regulated counterpart, achieving this performance without the use of chemical inducers or thermal shifts. This product-responsive dynamic control approach offers a costeffective and scalable alternative for industrial microbial fermentation, highlighting its value in next-generation biomanufacturing platforms.