Interested in recovering resource from process water and syngas to meet the current and future energy demand of single cell protein production industry? In purple4life, we will exam the use of hydrogen and carbon monoxide-rich off gas from a biogas SOFC as an alternative energy source for photoheterotrophic cultivation of purple bacteria, targeting their use as fish feed and food supplement. Do you like operating a photobioreactor under switching conditions to cultivate purple non sulphur bacteria, like R. rubrum?