Metabolic engineering of Arabidopsis and Brassica for poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer production

Poly(hydroxyalkanoates) are natural polymers with thermoplastic properties. One polymer of this class with commercial applicability, poly(3-hydroxybut yrate-co-3-hydroxyvale) (PHBV) can be produced by bacterial fermentation, b ut the process is not economically competitive with polymer production from petrochemicals, Poly(hydroxyalkanoate) production in green plants promises much lower costs, but producing copolymer with the appropriate monomer com position is problematic. In this study, we have engineered Arabidopsis and Brassica to produce PHBV in leaves and seeds, respectively, by redirecting the metabolic flow of intermediates from fatty acid and amino acid biosynth esis. We present a pathway for the biosynthesis of PHBV in plant plastids, and also report copolymer production, metabolic intermediate analyses, and pathway dynamics.