Water is abundant and so is sunlight, and using them to create hydrogen makes sense for a cleaner energy future, where biological systems powered by sunlight can manufacture hydrogen to use as fuel.

The way that plants produce hydrogen by splitting water has been poorly understood but answers are getting closer. A research team created a protein which, when exposed to light, displays the "electrical heartbeat" that is the key to photosynthesis. 

The system uses a naturally-occurring protein and does not need batteries or expensive metals, meaning it could be affordable in developing countries. 




Dr. Kastoori Hingorani. Credit: Stuart Hay, ANU

The team modified a much-researched and ubiquitous protein, Ferritin, which is present in almost all living organisms. Ferritin's usual role is to store iron, but the team removed the iron and replaced it with the abundant metal, manganese, to closely resemble the water splitting site in photosynthesis. 

The protein also binds a haem group, which the researchers replaced with a light-sensitive pigment, Zinc Chlorin. When they shone light onto the modified ferritin, there was a clear indication of charge transfer just like in natural photosynthesis.

The possibilities inspired visionary researcher Associate Professor Warwick Hillier, who led the research group until his death from brain cancer, earlier this year.

"Associate Professor Hillier imagined modifying E. coli so that it expresses the gene to create ready-made artificial photosynthetic proteins. It would be a self-replicating system – all you need to do is shine light on it," said Dr. Kastoori Hingorani, from the ARC Centre of Excellence for Translational Photosynthesis in the Australian National University Research School of Biology.