UK and Chinese scientists build microbial factories to produce hydrogen from air

In the UK, scientists have built tiny droplet-based microbial factories that produce hydrogen, instead of oxygen, when exposed to daylight in air. The findings of the international research team based at the University of Bristol and Harbin Institute of Technology in China, are published in Nature Communications.

The team trapped around 10,000 algal cells in each droplet, which were then crammed together by osmotic compression. By burying the cells deep inside the droplets, oxygen levels fell to a level that switched on special enzymes called hydrogenases that hijacked the normal photosynthetic pathway to produce hydrogen. In this way, around a quarter of a million microbial factories, typically only one-tenth of a millimeter in size, could be prepared in one milliliter of water.

To increase the level of hydrogen evolution, the team coated the living micro-reactors with a thin shell of bacteria, which were able to scavenge for oxygen and therefore increase the number of algal cells geared up for hydrogenase activity.

Although still at an early stage, the work provides a step towards photobiological green energy development under natural aerobic conditions.