Cyanobacteria helped shape life on Earth billions of years ago by producing oxygen through photosynthesis. Today, scientists see those same microorganisms as potential tools for clean energy production, especially in the race to develop sustainable hydrogen fuel.

Researchers in Germany and Portugal have now developed a new method that keeps hydrogen-producing cyanobacteria active for longer periods. The breakthrough addresses one of the biggest challenges in biological hydrogen production: oxygen interference.

The international team designed an electrochemical system that protects sensitive enzymes inside cyanobacteria from oxygen damage during photosynthesis. Their findings appeared in the journal Angewandte Chemie International Edition and could support future renewable hydrogen technologies.

Oxygen challenge addressed

Hydrogen has become a major focus in the global clean energy sector. Governments and companies across the United States continue investing heavily in low-carbon hydrogen systems for transportation, manufacturing, aviation, and power generation. However, producing hydrogen without fossil fuels remains costly and technically difficult.

Cyanobacteria, often called blue-green algae, naturally perform photosynthesis using sunlight, water, and carbon dioxide. Under certain conditions, they can also produce hydrogen gas. That ability makes them attractive for renewable energy research because they do not rely on traditional industrial fuel sources.

The problem comes from oxygen. During photosynthesis, cyanobacteria release oxygen, which quickly damages hydrogenase enzymes responsible for hydrogen production.

Researchers have struggled with that contradiction for years. Existing methods often require extra chemicals or external carbon sources to remove oxygen. Those approaches increase costs and reduce sustainability. Some systems also consume additional energy, limiting large-scale applications.

The new study introduces a different solution that avoids many of those drawbacks.

Polymer creates safe zone

Scientists from the University of Kassel, Ruhr University Bochum, and NOVA University Lisbon embedded cyanobacterial cells inside a specially designed redox polymer attached to an electrode.

The polymer contains viologen groups that react when researchers apply an electrical potential. That reaction removes oxygen directly around the cells, creating a localized oxygen-free environment.

By shielding hydrogenases from oxygen exposure, the enzymes continue operating for longer periods. The setup allowed continuous hydrogen production while the microorganisms still carried out photosynthesis under light exposure.

Researchers described the process as an important step toward scalable biological hydrogen production. Unlike conventional hydrogen systems, the setup relies on living organisms that may repair themselves naturally over time.

“Our approach combines the advantages of living cells with the precision of electrochemical systems,” said Prof. Dr. Kirstin Gutekunst from Kassel. She added that the technology could help future biophotovoltaic systems convert sunlight directly into hydrogen fuel more efficiently.

Engineered cells improve output

The team also genetically modified cyanobacteria to improve performance further. Researchers linked hydrogenase enzymes directly to Photosystem I, a central component of photosynthesis.

Those engineered strains produced hydrogen more consistently and for longer periods than natural cyanobacteria inside the same polymer system. Scientists believe the findings could help develop next-generation renewable energy systems that combine biology and electrochemistry for cleaner hydrogen production.

The study is published in the journal Angewandte Chemie International Edition.