'Artificial photosynthesis' project enters second phase

Evonik and Siemens’ joint Rheticus project has entered its second phase, as the companies combine the bioreactor and electrolyser elements of phase 1 into a test facility, scheduled to begin operations next year, that will use renewable energy and microorganisms to convert carbon dioxide and water into specialty chemicals and fuels. The project is funded by a €3.5m grant from Germany’s Federal Ministry of Education and Research.

The new plant will be built at Evonik’s site in Marl, near Munster. In its first stage, using technology developed by Siemens, carbon dioxide and water are converted to carbon monoxide and hydrogen in electrolysers. These gases pass into a bioreactor, developed by Evonik, where microorganisms convert them into useful chemical compounds. The companies refer to this as artificial photosynthesis because it combines chemical and biological steps to utilise energy to produce chemicals from carbon dioxide and water, although unlike natural photosynthesis, the energy is not in the form of light.