Energy metabolism coordination for the byproduct-free biosynthesis of 1,3-propanediol in Escherichia coli.

The efficient, byproduct-free production of 1,3-propanediol (1,3-PDO), a valuable chemical widely used in various industries, presents a significant challenge in bio-based manufacturing, due to its reduced nature. In this study, Escherichia coli K12 was engineered to achieve high-yield 1,3-PDO production by optimizing glucose metabolism and utilizing glycerol as a feedstock. Glycolytic flux was rerouted to the NADPH-generating pentose phosphate (PP) pathway, linking NADPH regeneration to 1,3-PDO biosynthesis. These modifications enhanced carbon utilization and eliminated byproduct formation. The engineered strain, PK19-D1Q1, achieved a record 1,3-PDO titer of 1.06 mol/L, with glycerol and glucose yields of 0.99 mol/mol and 2.01 mol/mol, respectively, in fed-batch fermentation. Furthermore, the strain's ability to maintain high productivity with crude glycerol underscores its potential for industrial-scale applications using low-cost, sustainable substrates. This study sets a benchmark for scalable, sustainable 1,3-PDO production, showcasing the integration of cofactor balancing and pathway engineering for bio-based chemical manufacturing.