Bioelectricity generation from live marine photosynthetic macroalgae

Area of Science:

• Biotechnology
• Renewable Energy
• Photosynthesis

Background:

• Bio-photoelectrochemical cells (BPECs) typically use unicellular microorganisms for solar energy conversion.
• Harvesting electrons from intact, multicellular photosynthetic organisms in BPECs remains largely unexplored.

Purpose of the Study:

• To investigate the potential of using intact marine macroalgae (seaweeds) in BPECs for efficient solar energy conversion.
• To characterize the electrical current generation from macroalgae-based BPECs.

Main Methods:

• Development of BPECs utilizing live marine macroalgae in natural seawater or saline buffer.
• Measurement of electrical current densities under light-dependent and light-independent conditions.
• Inhibition studies using Photosystem II inhibitors to identify electron sources.

Main Results:

• BPECs with macroalgae achieved photocurrent densities exceeding 50 mA/cm², significantly higher than microbial BPECs.
• Light-driven electron generation is linked to photosynthetic water oxidation, confirmed by inhibitor studies.
• Electrons are transferred to the anode via NADPH and other reduced molecules.

Conclusions:

• Intact marine macroalgae can be effectively used in large-scale BPECs for bias-free photocurrent generation.
• This approach offers a promising pathway for developing low-cost, sustainable solar energy conversion technologies.
• Macroalgae-based BPECs represent a significant advancement over microbial systems for clean energy production.