Travail de fin d'études: "Extractive fermentation of 3-hydroxypropionic acid: exploring bioprocess intensification paths through experiments and models"

Abstract

3-hydroxypropanoic acid (3-HP) is one of the platform molecules that have gained prominence due to its economic importance and versatility. As such, there is a growing need to find bioproduction routes for the purposes of sustainability and the circular economy. However, the bottlenecks of the route are associated with its production processes and its recovery. In this study, the impact of 3-HP on the bioconversion of 1,3-PDO by Acetobacter cerevisiae is investigated. The impact of 3 different 3-HP external additions (10g/L, 20g/L and 50g/L) and control were included in the cultural broth. The impact was assessed based on the pH evolution, biomass concentration, specific growth rate and specific production rate. The 2nd phase of this study focused on the recovery of 3-HP using reactive extraction with an organic phase prepared with tertiary amine TOA and diluents dodecane and dodecanol. The contact time between 3-HP and the organic phase was for 72 hours. The level of extraction was assessed on pH evolution from the initial to the equilibrium phase of the aqueous phase. The aqueous phase was also assessed for the 3-HP concentrations using HPLC. The impact of 50g/L external 3-HP additions significantly affected the specific production and growth rates in comparison to the control experiment. The control and 10g/L external 3-HP additions had almost the same effect while 20g/L external 3-HP additions had a slight effect on the growth parameters. The reactive extraction with TOA as a tertiary amine yielded very poor extraction yields as compared to bibliographic studies. Hypotheses such as the mode of storage of purified amines and the organic phases and the impact of impurities are discussed.