Develop 'metabolic-switch' based control strategy for energy-efficient photoheterotrophic versus chemoautotrophic purple non-sulfur bacteria cultivation in photobioreactors.

Job description
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.

We offer a 2-year EngD, embedded within the research project Purple4Life (Purple4Life | Sustainable innovation for a healthier and circular food future), funded under grant agreement Grant Agreement No. 101212806 under Circular Biobased Europe Joint Undertaking as part of Horizon Europe. The goal of the overall project is

• Develop safe and cost-effective PPB bioprocesses.
• Demonstrate PPB applications in food and feed chains.
• Assess nutritional, environmental, and health impacts of PPB.
• Enhance public awareness and societal acceptance.
• Promote exploitation and long-term sustainability of PPB technologies.

Your project, is part of WP1, in which various cultivation strategies for feed and food applications are being developed using different PPB's. Your specific project is to cultivate PPB while alternating microbial energy sources for the cultivation of phototrophic bacteria. You will determine the growth rate and yield and composition of PPB (R.rubrum) on synthetic fruit juice processing water using either near infrared light and/or syngas as energy source in short-term laboratory experiments. Then you will use the results as input to design, operate and evaluate the reactor control for a continuous reactor cultivation system.

Activities in this position include:

1) batch experiments and microbial culture assessment;
2) kinetic modelling, similar to the PBM;
3) design a control strategy for a continuous reactor system;
4) operate continuous reactor with control strategy
5) evaluate through impact assessment the proposed reactor control.
Laboratory analyses will be carried out on samples collected in the lab or at project partners. All of the above activites serve as a basis for developing an optimized programmable logic controller for a light-efficient photobioreactor that enables cultivation of PPB in the light and the dark.

Your work will be carried out under the guidance of Dr. Samarpita Roy (section Environmental Biotechnology, faculty of Applied Sciences, Delft University of Technology), Dr. Mar Palmeros Parada, and Dr. Ralph Lindeboom (Department of Water Management, TU Delft) and you have the opportunity to work in both groups depending on research progress.

The project also involves frequent collaboration with other WP1 and WP2 and Purple4Life researchers at amongst others UMons, UAntwerpen, URJC Madrid and Imperial College.

Job requirements
Required skills:

• Relevant Master degree in Environmental Sciences/Engineering/Microbiology, Earth Sciences, Chemical Engineering, or a related field
• Fluency and effective communication in English, both written and oral
• Experimental Microbiology or bioreactor design and control

The following skills are preferred:

• Microbiology lab skills or bioreactor design and control
• Experience in kinetic modelling of microbial cultures
• Pro-active communication skills and a desire and ability to work well in a team

TU Delft (Delft University of Technology)
Delft University of Technology is built on strong foundations. As creators of the world-famous Dutch waterworks and pioneers in biotech, TU Delft is a top international university combining science, engineering and design. It delivers world class results in education, research and innovation to address challenges in the areas of energy, climate, mobility, health and digital society. For generations, our engineers have proven to be entrepreneurial problem-solvers, both in business and in a social context.

At TU Delft we embrace diversity as one of our core values and we actively engage to be a university where you feel at home and can flourish. We value different perspectives and qualities. We believe this makes our work more innovative, the TU Delft community more vibrant and the world more just. Together, we imagine, invent and create solutions using technology to have a positive impact on a global scale. That is why we invite you to apply. Your application will receive fair consideration.

Challenge. Change. Impact!

Faculty of Civil Engineering and Geosciences
The Faculty of Civil Engineering & Geosciences (CEG) is committed to outstanding international research and education in the field of civil engineering, applied earth sciences, traffic and transport, water technology, and delta technology. Our research feeds into our educational programmes and covers societal challenges such as climate change, energy transition, resource availability, urbanisation and clean water. Our research projects are conducted in close cooperation with a wide range of research institutions. CEG is convinced of the importance of open science and supports its scientists in integrating open science in their research practice. The Faculty of CEG comprises 28 research groups in the following seven departments: Materials Mechanics Management & Design, Engineering Structures, Geoscience and Engineering, Geoscience and Remote Sensing, Transport & Planning, Hydraulic Engineering and Water Management.

Click here to go to the website of the Faculty of Civil Engineering & Geosciences.

Conditions of employment
We offer you a program where you will solve a practical, integrative, and complex problem in cooperation with nutrition and fish cultivation sector. You study, on average, two days per week at the TU Delft, following dedicated courses, and apply your learning three days per week on the project in practice.

TU Delft offers EngD-candidates a 2-year contract, with an official go/no go progress assessment after one year. Salary and benefits are in accordance with the Collective Labour Agreement for Dutch Universities, based on scale TOIO and equivalent to those of a doctoral candidate. In the first year, you'll receive a gross monthly salary of €2901,- increasing to a maximum of €3378,- in the second year.

TU Delft offers a customizable compensation package, discounts on health insurance and sports memberships, and a monthly work costs contribution. Flexible work schedules can be arranged.

Additional information
For more information about this vacancy, please contact Dr. Ralph Lindeboom (r.e.f.lindeboom@tudelft.nl), Dr. Mar Palmeros Parada (M.D.M.PalmerosParada@tudelft.nl), or dr. Samarpita Roy (s.roy@tudelft.nl) or consult the Purple4Life webpage.

Application procedure
Are you interested in this vacancy? Please apply no later than 18 August 2025 via the application button and upload the following documents:

• Short motivation letter (max. 1 page) covering your research interests and relevant experience for this position
• 1-2 page CV and names, e-mail addresses, and telephone numbers of two references (unless reference letters are attached)
• Copies of academic qualifications including list of courses and marks

Interviews will be held during the last week of August.
Intended starting date is 1 October 2025.

You can address your application to Ralph Lindeboom.

Please note:

• You can apply online. We will not process applications sent by email and/or post.
• A pre-employment screening can be part of the selection procedure.
• For the final candidates, a knowledge security check will be part of the application procedure. For more information on this check, please consult Chapter 8 of the National Knowledge Security Guidelines. We carry out this check on the basis of legitimate interest.
• Please do not contact us for unsolicited services.