title: Impact of sustaining a controlled residual growth on polyhydroxybutyrate yield and production kinetics in Cupriavidus necator.
abstract: In this study a complementary modeling and experimental approach was used to explore how growth controls the NADPH generation and availability, and the resulting impact on PHB (polyhydroxybutyrate) yields and kinetics. The results show that the anabolic demand allowed the NADPH production through the Entner-Doudoroff (ED) pathway, leading to a high maximal theoretical PHB production yield of 0.89 C mole C mole(-1); whereas without biomass production, NADPH regeneration is only possible via the isocitrate dehydrogenase leading to a theoretical yield of 0.67 C mole C mole(-1). Furthermore, the maximum specific rate of NADPH produced at maximal growth rate (to fulfil biomass requirement) was found to be the maximum set in every conditions, which by consequence determines the maximal PHB production rate. These results imply that sustaining a controlled residual growth improves the PHB specific production rate without altering production yield.
authors.affiliation: Université de Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077 Toulouse, France; INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, F-31400 Toulouse, France; CNRS, UMR5504, F-31400 Toulouse, France; VEOLIA Environnement, Centre de Recherche sur l'Eau, Chemin de la Digue, BP 76, F-78603 Maisons-Laffitte Cedex, France. Electronic address: estelle.grousseau@insa-toulouse.fr.
authors.forename: Estelle
authors.initials: E
authors.lastname: Grousseau
authors.forename: Elise
authors.initials: E
authors.lastname: Blanchet
authors.forename: Stéphane
authors.initials: S
authors.lastname: Déléris
authors.forename: Maria G E
authors.initials: MG
authors.lastname: Albuquerque
authors.forename: Etienne
authors.initials: E
authors.lastname: Paul
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Uribelarrea
mesh_terms: D061249:Batch Cell Culture Techniques; D020148:Butyric Acid / Q000494:pharmacology; D002244:Carbon / Q000494:pharmacology; D003198:Computer Simulation; D020118:Cupriavidus necator / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D006885:Hydroxybutyrates / Q000378:metabolism*; D007700:Kinetics; D011091:Polyesters / Q000378:metabolism*; D013997:Time Factors; D000094122:Polyhydroxybutyrates
chemical_list: D020148:Butyric Acid; D002244:Carbon; D006885:Hydroxybutyrates; D011091:Polyesters; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates
keywords: Cupriavidus necator; Fed-Batch fermentation; Metabolic Flux Analysis (MFA); Polyhydroxybutyrate (PHB); Volatiles fatty acids (VFA)