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? Would you like to deepen your technical expertise, gain practical experience with the design, operation and evaluation of innovative photobioreactor solutions, and earn a Doctor of Engineering (EngD) accreditation? The Civil Engineering and Geosciences Faculty of Delft University of Technology (TU Delft) offers a degree program where you will solve a practical, integrative, and complex problem in cooperation with private project partners. As an EngD candidate, you study, on average, two days per week at the TU Delft, following dedicated courses, and apply your learning three days per week on your individual design project.