Travail de fin d'études en chimie et bio-industries : Intensification of aerobic gas fermentation with Cupriavidus necator via strain and process development.

Abstract

C. necator’s natural ability to use CO2 and H2 makes it useful to tackle harmful concentration of CO2 in atmosphere, while it is not CO2 and H2 efficient which makes it significantly less economically viable. Hydrogen prices have reached €1.50 to €2.50 /kilogram, depending on production costs (Curcio et al., 2025). The aim of this thesis was to intensify aerobic gas fermentation via two approaches i.e., process development and strain engineering. Several experimental and technical methods were studied and applied concerning the enhancement of CO2 fixation. Additionally, cryopreservation of C. necator strain DSM 545 was tested at both -20 °C and -80 °C. Regarding process development, different medium compositions were tested and C. necator’s gas fermentation process was scaled up from 1 L reactor volume to 24 L reactor volume. Additionally, a provided metabolically engineered strain (i.e., induced carboxysome approach) was tested in terms of CO2 efficiency and biomass production.