Reconfiguring the Escherichia coli Electron Transport Chain to Enhance trans-2-Decenoic Acid Production

trans-2-Decenoic acid is a pivotal α,β-medium-chain unsaturated fatty acid that serves as an essential intermediary in the synthesis of 10-hydroxy-2-decenoic acid and various pharmaceutical compounds. Biosynthesis yield of trans-2-decenoic acid by decanoic acid has significantly improved in recent years; however, the oxidative stress of Escherichia coli at high fatty acid concentrations restricts the conversion rate. Here, we introduced a combination of rational design and metabolic rewiring of the E. coli electron transport chain (ETC) to improve trans-2-decenoic acid production. Overexpressing ubiquinone (UbQ) biosynthesis genes enhanced the expression of ETC complex III: UbQ to reduce reactive oxygen species (ROS) accumulation. Furthermore, applying rotenone to inhibit ETC complex I improved the electron transfer efficiency of complex II. The integration of Vitamin B₅ and B₂ into the fermentation process increased the activities of fatty acyl-CoA synthetase (^MaMACS) and fatty acyl-CoA dehydrogenase (^PpfadE). Finally, the constructed E. coli BL21(DE3)(ΔfadBJR/pCDFDuet-1-^PpfadE-^MaMACS/pRSFDuet-1-sumo-^CtydiI-ubiI) strain exhibited a 51.50% decrease in ROS and a 93.33% enhancement in trans-2-decenoic acid yield, reaching 1.45 g/L after 66 h, which is the highest yield reported for flask fermentation. This study reports the feasibility of rewiring the ETC regulation and energy metabolism to improve α,β-UCA biosynthesis efficiency.