Targeted poly(3-hydroxybutyrate-co-3-hydroxyvalerate) bioplastic production from carbon dioxide

[Display omitted] •Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was produced through fermentation.•The productivity for mixotrophic fermentation with a pH-stat was 0.87 g L−1 h−1.•A physical model for mixotrophic PHBV production was developed for the first time.•The model was calibrated and validated with independent and distinct experiments.•1H-NMR and 13C-NMR analysis confirmed the predicted micro structure of PHBV. A microbial production process was developed to convert CO2 and valeric acid into tailored poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) bioplastics. The aim was to understand microbial PHBV production in mixotrophic conditions and to control the monomer distribution in the polymer. Continuous sparging of CO2 with pulse and pH-stat feeding of valeric acid were evaluated to produce PHBV copolyesters with predefined properties. The desired random monomer distribution was obtained by limiting the valeric acid concentration (below 1 gL-1). 1H-NMR, 13C-NMR and chromatographic analysis of the PHBV copolymer confirmed both the monomer distribution and the 3-hydroxyvalerate (3HV) fraction in the produced PHBV. A physical-based model was developed for mixotrophic PHBV production, which was calibrated and validated with independent experimental datasets. To produce PHBV with a predefined 3HV fraction, an operating diagram was constructed. This tool was able to predict the 3HV fraction with a very good accuracy (2% deviation).