Microbial factories that produce hydrogen instead of oxygen when exposed to daylight in the air will help create a clean energy source. Details about the new development of scientists are reported by the journal Nature Communications.

Usually, algal cells fix carbon dioxide and produce oxygen through photosynthesis. A study by scientists from the University of Bristol and Harbin Institute of Technology used sugar droplets. They were filled with living algal cells to produce hydrogen, not oxygen, through photosynthesis.

Hydrogen is potentially a climate-neutral fuel and is being considered as an energy source in the future. The main disadvantage of hydrogen fuel is that it requires a lot of energy to produce. A cleaner alternative is needed, and this discovery could be an important step forward.

To force the algae to produce hydrogen, it is necessary to limit the intake of sulfur, one of the important cellular protein components. In response, the algae slow down the metabolism, and the excess energy formed during photosynthesis releases into the environment in the form of hydrogen. It is formed from water under the action of a catalyst – a hydrogenase enzyme. In nature, algae’s defense mechanism is triggered only in “hungry” times, and, in general, the release of hydrogen is very insignificant.

To increase hydrogen production, the scientists covered living microreactors of sugar droplets with algal cells inside a thin shell of bacteria. They absorb oxygen and, therefore, increase the number of algal cells adapted to hydrogenase activity.

Although this work is still in its early stages, it represents a step towards developing photobiological green energy in natural aerobic conditions.