Résumé
•Carbon distribution of propionic acid between 3HB and 3HV monomers was investigated.•Limiting phosphorus feeding leads to a maximum of 33% (Mole.Mole−1) of 3HV.•Phosphorus deficiency leads to an instant production of up to 100% of 3HV.•But the increase in phosphorus limitation degree decreases PHA productivity.•Mechanisms defining PHA composition differed depending on the limitation (N or P).
Properties of polyhydroxybutyrate-co-hydroxyvalerate (P(3HB-co-3HV)) depend on their 3HV content. 3HV can be produced by Cupriavidus necator from propionic acid. Few studies explored carbon distribution and dynamics of 3HV and 3HB monomers production, and none of them have been done with phosphorus as limiting nutrient. In this study, fed-batch cultures of C. necator with propionic acid, as sole carbon source or mixed with butyric acid, were performed. Phosphorus deficiency allowed sustaining 3HV production rate and decreasing 3HB production rate, leading to an instant production of up to 100% of 3HV. When a residual growth is sustained by a phosphorus feeding, the maximum 3HV percentage produced from propionic acid is limited to 33% (Mole.Mole−1). The association of a second carbon source like butyric acid lead to higher conversion of propionic acid into 3HV. This study showed the importance of the limiting nutrient and of the culture strategy to get the appropriate product.