Table 1.

Metabolic model of PHA production from mixtures of acetate and propionate by mixed microbial cultures

Reaction	Stoichiometry
R1: Acetate Uptake	CH2O + ATP → CHO0.5 + 0.5·H2O
R2: Propionate Uptake	${\text{CH}}_2{\text{O}}_{\raisebox{1ex}{$2$}\!\left/ \!\raisebox{-1ex}{$3$}\right.}$ + 0.67·ATP → ${\text{CH}}_{\raisebox{1ex}{$4$}\!\left/ \!\raisebox{-1ex}{$3$}\right.}{\text{O}}_{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$3$}\right.}$ + 0.33·H2O
R3: Propionyl-CoA converted to Acetyl-CoA	1.5·${\text{CH}}_{\raisebox{1ex}{$4$}\!\left/ \!\raisebox{-1ex}{$3$}\right.}{\text{O}}_{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$3$}\right.}$ + H2O → CHO0.5 + 1.5·NADH2 + 0.5·CO2
R4: Growth on Acetyl-CoA	1.27·CHO0.5 + 0.2·NH3 + K1·ATP + 0.3·H2O → CH1.4N0.2O0.4 + 0.53·NADH2 + 0.27·CO2
R5: Growth on Propionyl-CoA	1.06·${\text{CH}}_{\raisebox{1ex}{$4$}\!\left/ \!\raisebox{-1ex}{$3$}\right.}{\text{O}}_{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$3$}\right.}$ + 0.2·NH3 + K2·ATP + 0.17·H2O → CH1.4N0.2O0.4 + 0.47·NADH2 + 0.06·CO2
R6: Catabolism	CHO0.5 + 1.5·H2O → CO2 + 2·NADH2 + 0.5·ATP
R7: Maintenance	ATP → mATP
R8: Oxidative Phosphorylation	NADH2 + 0.5·O2 → H2O+δ·ATP
R9: Acetyl-CoA* Production	CHO0.5 + 0.25·NADH2 → CH1.5O0.5
R10: Propionyl-CoA* Production	${\text{CH}}_{\raisebox{1ex}{$4$}\!\left/ \!\raisebox{-1ex}{$3$}\right.}{\text{O}}_{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$3$}\right.}$ + 0.17·NADH2 → ${\text{CH}}_{\raisebox{1ex}{$5$}\!\left/ \!\raisebox{-1ex}{$3$}\right.}{\text{O}}_{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$3$}\right.}$
RPHB: PHB Production	CH1.5O0.5 → PHB
RPHV: PHV Production	0.4·CH1.5O0.5 + 0.6·${\text{CH}}_{\raisebox{1ex}{$5$}\!\left/ \!\raisebox{-1ex}{$3$}\right.}{\text{O}}_{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$3$}\right.}$ → PHV
RPH2MV: PH2MV Production	${\text{CH}}_{\raisebox{1ex}{$5$}\!\left/ \!\raisebox{-1ex}{$3$}\right.}{\text{O}}_{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$3$}\right.}$ → PH2MV