Living Diatom Microalgae for Desiccation-Resistant Electrodes in Biophotovoltaic Devices

Area of Science:

• Renewable Energy
• Biotechnology
• Microbiology

Background:

• Renewable energy research explores photosynthetic microorganisms for sustainable power.
• Green microalgae are established in biophotovoltaic (BPV) cells, but diatoms remain largely unexamined.
• Diatoms are abundant, adaptable, and resilient to environmental stressors, suggesting potential for BPV applications.

Purpose of the Study:

• To investigate the potential of various diatom species as biophotoconverters in BPV cells.
• To evaluate the impact of environmental factors on photocurrent generation by diatoms.
• To assess the durability and desiccation resistance of diatom-based biophotoanodes.

Main Methods:

• Coating indium tin oxide photoanodes with four diatom species: *Phaeodactylum tricornutum*, *Thalassiosira weissflogii*, *Fistulifera pelliculosa*, and *Cylindrotheca closterium*.
• Testing BPV cells under varying light intensities, cell densities, chlorophyll content, and mediator concentrations.
• Assessing photoactivity after prolonged dehydration and rewetting cycles, comparing with *Dunaliella tertiolecta*.

Main Results:

• Diatoms were successfully utilized as biophotoconverters in a model BPV cell.
• Photocurrent generation efficiency was influenced by light intensity, cell density, chlorophyll content, and mediator concentration.
• Diatom-based photoanodes, particularly *T. weissflogii*, demonstrated significant photoactivity after 15 days of dehydration and four rewetting cycles, exceeding the performance of green microalgae.

Conclusions:

• Diatoms are suitable photosynthetic microorganisms for BPV devices.
• Diatom-based biophotoanodes exhibit superior desiccation resistance compared to those made from green microalgae.
• This research paves the way for developing robust and durable BPV devices utilizing diatoms.