Conductive Characterization of <i>Pseudomonas aeruginosa</i> -Derived Nanowires for Bioelectrochemical Systems

Microbial nanowires represent a powerful natural solution for bioelectronic energy conversion, enabling long-distance extracellular electron transfer (EET) within microbial fuel cells (MFCs). In this study, nanowires produced by strain <i>Pseudomonas aeruginosa</i> SKVM1 were isolated, purified, and electrochemically characterized to evaluate their bifunctional electrocatalytic potential. Morphological confirmation using FESEM, EDS, and HRTEM revealed uniform filamentous structures with diameters of 10-30 nm and micrometer-scale lengths, forming a 3D entangled scaffold. Electrochemical characterization was performed by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS). CV data confirmed distinct and stable redox peaks at 0.30 and 0.27 V, indicating a cytochrome-mediated pseudocapacitance. A significant highlight of this work is the application of these nanowires in water-splitting catalysis. EIS demonstrated low charge-transfer resistance and a characteristic Warburg tail. This indicated efficient electron conduction combined with diffusion-limited ionic transport. LSV and Tafel analyses showed consistent scan-rate-dependent kinetics, with the optimal kinetic resolution occurring at 30 mV s^-1, yielding Tafel slopes (OER: 414 mV dec^-1; HER: 259 mV dec^-1). The finding suggests that the SKVM1 nanowires act as a proton wire and a biological mimic of the oxygen evolving complex (OEC), stabilizing reactive intermediates through a self-assembling protein matrix. This work advances the findings of nanowire-mediated conductivity. Future research directions include the genetic optimization of PilA subunits to enhance intrinsic conductivity and the integration of biohybrid scaffolds into MFCs and green hydrogen electrolyzers.