Lettinga Award 2017 for ‘dark photosynthesis’

ETE scientists David Strik, Mathijs van der Zwart and Cees Buisman were awarded the 2017 Gatze Lettinga award. Since 2001 this prize of 10.000 euro is awarded every two to three years at the Anaerobic Digestion congress of the International Water Association. This award is to stimulate and implement anaerobic cleaning technology in society. The 2017 award was sponsored by Paques, Biothane and LeAF. The focus of this year’s call was closing resource cycles using anaerobic technology. The jury concluded that the winning proposal ‘Dark photosynthesis: anaerobic biosynthesis of food from wastewater and electricity’ had the most potential. 

More pressure
Due to the growing world population, there will be an increasing demand for food. The resulting increase in agricultural activities will put even more pressure on natural areas, like grasslands and forests. ’When we manage to grow plants without sunlight, I call it dark photosynthesis, we can produce food in areas unsuitable for traditional agriculture’, says ETE scientist and prize winner David Strik. Instead of culturing crops on farmland, the scientists plan to grow food in a bioreactor in an energy and water efficient way.

Plants under power
For most plants the sun is essential for growth. During photosynthesis, sunlight is used to oxidize water, generating electrons. These electrons play a key role in biomass production, i.e. growth. If electrons are directly supplied to growing plants by running electricity through them, light is not needed anymore and plants may grow in the dark. Strik: ‘We want to put plants under power, so they can grow without light.’ By providing nutrient-rich wastewater, for example urine, high quality food can be grown. This principle is already functioning in bacteria: these organisms produce acetic acid using electricity and CO₂.

Close cycles
With the award, the scientists intend to expand their research. Their next step will be to use urine as a nutrient source and test ‘dark photosynthesis’ on selected photosynthetic microorganisms. It is explorative research, but if the team gets this idea working, there will be an alternative method to produce food. ‘I do hope our research will inspire other researchers to use waste water as a resource and close cycles in a clean and sustainable way’, says Strik. ‘A circular economy is simply a necessity.’