Sunlight-Powered Device Converts CO₂ into Bacterial Biomass

A new study published in the Journal of the American Chemical Society describes an innovative device that uses sunlight to convert carbon dioxide and water into bacterial biomass—without the need for plants, algae, or photosynthetic microbes.

How It Works

The device combines an organic solar cell, a semiconductor electrode, two enzymes, and engineered Escherichia coli (E. coli) in a single liquid system. Sunlight drives the splitting of water to produce oxygen, while an enzyme converts CO₂ into formate. The engineered E. coli then uses formate as an energy source to grow.

“The integrated system allows synthetic biologists to plug in different engineered E. coli strains for different molecules.”
– Dr. Lin Su, Queen Mary University of London

Background

The chemical industry currently depends heavily on fossil fuels. Two alternative approaches—solar-powered chemistry and engineered bacteria—have shown promise, but integrating both in a single reactor has proven difficult.

Previous biohybrid devices used different combinations of catalysts and organisms. This study is distinct in using components that can be independently tuned: an organic light absorber, a purified enzyme, formate as an energy carrier, and engineered E. coli.

Key Advancements

The study demonstrates the full chain from photons to E. coli biomass in one liquid. This system could be modified to produce target chemicals other than biomass.

Dr. Celine Wing See Yeung (University of Cambridge) described the project as “a jigsaw puzzle combining organic photovoltaics, enzyme purification, and synthetic biology.”

“This study shows synthetic light absorbers can be integrated with non-photosynthetic microbes to power natural photosynthesis reactions, opening opportunities for sustainable manufacturing.”
– Professor Erwin Reisner, University of Cambridge

Potential Applications

Professor Ron Milo (Weizmann Institute of Science) highlighted the importance of integrating both systems for sustainable production technologies, particularly for growing bacteria using CO₂ to produce food with less land and water.

Limitations

The technology remains at an early stage. Current yields are small, and reactor operation lasts only hours rather than weeks.

Publication

The study was published in the Journal of the American Chemical Society.