Binding-Enhanced Organic Semiconductor-Bacteria Hybrids for Efficient Visible Light-Driven CO₂ Conversion to...

Area of Science:

• Biotechnology
• Materials Science
• Photochemistry

Background:

• Semiconductor-biohybrids offer a promising route for solar-driven CO2 conversion to chemicals.
• Challenges remain in broadening light-harvesting and improving interfacial contact for higher efficiencies.

Purpose of the Study:

• To develop efficient organic semiconductor-biohybrids for CO2 photoreduction to poly-β-hydroxybutyrate (PHB).
• To enhance light absorption and interfacial interactions for improved solar-to-chemical conversion.

Main Methods:

• Hybridization of organic semiconductors (OSCs) with nonphotosynthetic bacteria (Ralstonia eutropha).
• Design of OSCs with extended conjugated backbones and zwitterionic choline phosphate side chains.
• Investigation of interfacial interactions and electron transfer mechanisms.

Main Results:

• OSC-biohybrids demonstrated efficient CO2 photoreduction to PHB under visible light.
• Optimal hybrids achieved a maximum PHB yield of 107.3 mg L-1 OD600-1.
• A CO2-to-PHB quantum efficiency of 1.14% was recorded, with continuous production over several days.

Conclusions:

• The developed OSC-biohybrids effectively endow nonphotosynthetic bacteria with photosynthetic capacity.
• This strategy enables efficient photoautotrophic PHB production comparable to heterotrophic fermentation.
• The approach presents a viable pathway for sustainable chemical synthesis using solar energy.