Work

Comparative effects of monochromatic red and broad-spectrum white light on biophotovoltaics: Stability, efficiency, and application potential

Year: 2025

Type: article

Abstract: Biophotovoltaic (BPV) systems offer a sustainable strategy for solar energy conversion by harvesting the oxygenic photoautotrophic electrons via the extracellular electron transfer (EET) pathway. The photosynthetic pigments absorb light to drive water splitting and generate reducing equivalents for both growth and EET, which thus defines BPV performance is closely tied to light quality. This study evaluated a ferricyanide-mediated BPV system under two light conditions: monochromatic 620-nm red light and broad-spectrum white light, each applied at low (50 μmol photons m −2 s −1 ) and high (300 μmol photons m −2 s −1 ) intensities. Ferricyanide was chosen as the most stable and practical mediator for long-term, outdoor applications. At low intensity, both light types yielded similar photocurrents. However, under high-intensity white light, ferricyanide degraded into toxic cyanide, disrupting cell viability and system function. In contrast, red light preserved mediator stability and significantly enhanced EET, even under very high intensity (up to 1200 μmol photons m −2 s −1 ). While stronger light did not improve cell growth, it boosted EET, emphasizing its role as a potential energy dissipation pathway. These findings highlight the importance of matching light quality to both microbial pigment absorption and mediator stability, and moreover, provide a viable strategy for outdoor BPV deployment. • Red light outperforms white light in sustaining performance under high intensity. • Strong white light degrades ferricyanide to cyanide, causing BPV system failure. • Red light keeps ferricyanide stable and boosts EET up to 1200 μmol photons m −2 s −1 . • Higher light absorbance boosts EET as an energy dissipation path, not cell growth. • Light filters can prevent ferricyanide loss, enabling long-term outdoor BPV use.

Source: Bioelectrochemistry

DOI: 10.1016/j.bioelechem.2025.109164

Authors: Jianqi Yuan, Bin Lai, Jens Olaf Krömer

Institution: Helmholtz Centre for Environmental Research

Language: English

Topic: Microbial Fuel Cells and Bioremediation

Subfield: Environmental Engineering

Field: Environmental Science

Domain: Physical Sciences

SDG: Affordable and clean energy

Open Access status: hybrid

Estimated APC paid: $3,970