Microbial fuel cells (MFCs) offer sustainable solutions for various biotechnological applications and are a crucial area of research in biotechnology. MFCs can effectively treat wastewater and biodiesel waste by decomposing organic matter and generating electricity. Certain Pseudomonas species possess extracellular electron transfer (EET) pathways, enabling them to transfer electrons from organic compounds to the MFC's anode. Moreover, Pseudomonas species can grow under low oxygen conditions, which is advantageous considering that the electron transfer process in an MFC typically leads to reduced oxygen levels at the anode. This study focuses on evaluating MFCs inoculated with a new Pseudomonas species, grown with 1 g.L-1 glycerol, a common byproduct of biodiesel production. Pseudomonas sp. BJa5 exhibited a maximum power density of 39 mW.m-2. Also, the observed voltammograms and genome analysis indicate the potential production of novel redox mediators by BJa5. Additionally, we investigated the bacterium's potential as a synthetic biology non model chassis. Through testing various genetic parts, including constitutive promoters, replication origins, and cargos using pSEVA vectors as a scaffold, we assessed the bacterium's suitability. Overall, our findings offer valuable insights into utilizing Pseudomonas spp. BJa5 as a novel chassis for MFCs. Synthetic biology approaches can further enhance the performance of this bacterium in MFCs, providing avenues for improvement.

The ability of some bacteria to perform Extracellular Electron Transfer (EET) has been explored in bioelectrochemical systems (BES) to obtain energy or chemicals from pure substances or residual substrates. Here, a new pyoverdine-producing Pseudomonas aeruginosa strain was isolated from a MFC biofilm oxidizing glycerol, a by-product of biodiesel production. Strain EL14 was investigated to assess its electrogenic ability and products. In an open circuit system (fermentation system) EL14 was able to consume glycerol and produce 1,3-propanediol, an unusual product from glycerol oxidation in P. aeruginosa. The microbial fuel cell (MFC), EL14 reached a current density of 82.4 mA m-2, during the first feeding cycle, then drops sharply as the biofilm falls off. Cyclic voltammetry suggests electron transfer to the anode occurrs indirectly, i.e., through a redox substance, with redox peaks at 0.22 and -0.45 V (vs Ag/AgCl) and directly probably by membrane redox-proteins with redox peak at 0.05 V (vs Ag/AgCl). EL14 produced added-value bioproducts, acetic and butyric acids, as well as 1,3 propanediol, in both fermentative and anodic conditions. However, the yield of 1,3-PDO from glycerol was enhanced from 0.57 to 0.89 (mol of 1,3-PDO mol-1 of glycerol) under MFC conditions compared with the fermentation. This result was unexpected since successful 1,3-PDO production is not usually associated with the P. aeruginosa glycerol metabolism. By comparing EL14 genomic sequences related to the 1,3-PDO biosynthesis with reference P. aeruginosa strains, we observed that strain EL14 has three copies of dhaT gene (1,3-propanediol dehydrogenase a different arrangement compared to other Pseudomonas isolates). Thus, this work functionally characterizes a bacterium never before associated to 1,3-PDO biosynthesis, indicating its potential for converting a by-product of the biodiesel industry into an emerging chemical product.