A vaccine bioreactor for Uganda

The brief

Design a small-scale bioreactor to grow yeast for a protein-subunit tuberculosis vaccine in Uganda, to reduce the risk of investing in a full-scale reactor.

Uganda is one of the WHO’s 30 high-burden TB countries, with over 91,000 new cases a year, 32% of them in people who are also HIV-positive. The current BCG vaccine is unsafe for immunocompromised patients. A yeast-derived protein-subunit vaccine is non-live and contains no DNA, which avoids that risk.

What I did

The team combined biomedical, chemical and biochemical engineering students.

• Integrated the three design subsystems (mixing, heating, and impedance probes for monitoring growth) into a single design.
• Organised and delegated the final report, bringing seven weeks of work from three disciplines into one short document.
• Worked on heating efficiency, mixing, real-time impedance monitoring, temperature control, shear stress reduction and cost analysis. Yeast cells are damaged by high shear, so mixing efficiency had to be balanced against cell viability.
• Contributed to the physical build and took the optical density measurements.

Result

The physical bioreactor completed a 24-hour trial without failure. I also wrote an individual social impact report covering siting and sustainability, including avoiding migratory herd routes and the risk of chemical leakage into waterways.