Unlocking 1,3-Propanediol Production by Pseudomonas aeruginosa through Electro-Fermentation

This study compares 1,3-propanediol (1,3-PDO) production from glycerol, a byproduct of the biodiesel industry, by traditional and electro-driven fermentation. 1,3-PDO is a building block for many polymers and a valuable chemical for various industrial applications. This is the first report about the use of Pseudomonas aeruginosa for 1,3-PDO production by electro-fermentation. Electro-fermentation assays were conducted in a single chamber equipped with carbon cloth and platinum electrodes, operated either with a power supply (ΔV: 0.01, 0.05, 0.3, or 0.4 V) or under potentiostatic control of 0.4 V vs Ag/AgCl and Cl^- (3 mol L^-1). Compared to traditional fermentation (control), applying different voltages boosted 1,3-PDO production. The highest 1,3-PDO concentration was achieved at 0.05 V: 99.49 ± 0.57 mmol L^-1, corresponding to a yield of 0.78 ± 0.01 mol of 1,3-PDO mol of glycerol^-1, a productivity of 15.70 ± 0.25 mmol L^-1 h^-1, and a ca. 100% increase compared to the control. Acetic and butyric acid concentrations also increased under electro-fermentation conditions. Electron balance showed that the electro-fermentation favored the reductive pathway for 1,3-PDO formation and that the electron recovery was 89.65 ± 0.37% compared to 45.14 ± 0.89% achieved with traditional fermentation. These findings demonstrate that electro-fermentation is an effective approach to modulate the metabolism of P. aeruginosa, enhancing the production of 1,3-PDO. Overall, this work expands the current understanding of the biotechnological potential of P. aeruginosa in bioelectrochemical systems and supports the integration of such processes into sustainable biorefineries.