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The development of bioelectrochemical systems requires careful selection of both their biotic and abiotic components to obtain sustainable devices. Herein, we report a biophotoelectrode obtained with polyhydroxybutyrate (PHB), a biopolymer, which purple non-sulphur bacteria produce as an energy stock under specific environmental conditions. The electrode was obtained by casting a mixture composed of PHB and carbon fibers in a 3:2 mass ratio. Following, the composite material was modified with polydopamine and thermally treated to obtain a hydrophilic electrode with improved electrochemical behavior. The bio-based electrode was tested with metabolically active cells of Rhodobacter capsulatus embedded in a biohybrid matrix of polydopamine. The system achieved enhanced catalytic activity under illumination, with an 18-fold increase in photocurrent production compared to biophotoelectrodes based on glassy carbon, reaching a current density of 12 ± 3 μ A cm−2, after 30 min of light exposure at +0.32 V. The presented biocompatible electrode provides a sustainable alternative to metal-based and critical raw material-based electrodes for bioelectrochemical systems. [ABSTRACT FROM AUTHOR]

Photobioelectrochemistry, biosensor, nitrophenol, purple bacteria, semiartificial photosynthesis Keywords: photobioelectrochemistry; biosensor; nitrophenol; purple bacteria; semiartificial photosynthesis EN photobioelectrochemistry biosensor nitrophenol purple bacteria semiartificial photosynthesis 1 1 1 06/20/23 20230614 NES 230614 B The Front Cover b represents how purple bacterial cells utilized in biohybrid electrochemical systems hit, or miss, their "target electrode" with photo-induced electrons depending on the concentration of dinitrophenol at which they are exposed. [Extracted from the article]