PhD defence

Unravelling serpin regulation in Bifidobacterium longum NCC 2705; from mechanisms to production conditions

PhD candidate S (Stéphane) Duboux
Promotor prof.dr. M (Michiel) Kleerebezem
External copromotor Dr. Annick Mercenier
Dr. Biljana Bogicevic
Organisation Wageningen University, Host Microbe Interactomics
Date

Fri 9 December 2022 16:00 to 17:30

Venue Omnia
Room Groot Auditorium

Summary

Bifidobacteria are amongst the first human gut colonizers. They are proposed to play key roles in the development of the infant and are hence today increasingly used as probiotics in early life nutrition. In this thesis we investigated the role that manufacturing may have on bifidobacterial bioactivity. Using the model strain B. longum NCC 2705 we demonstrated that growth conditions modulate the levels of an important health-promoting molecule it produces (i.e. serine protease inhibitor (serpin)). We showed that serpin production is dictated by the carbohydrates used for bacterial growth and that serpin-inducing galactose elicits a variety of physiological adaptations. Furthermore, we discovered that a novel sRNA plays a key-role in orchestrating these cell-wide adaptations. Overall, this thesis adds to our understanding of bifidobacterial physiology. We highlight the importance of understanding how the production of effector molecules is regulated, to develop effect-oriented, robust and reproducible probiotic products for specific health applications.