Abstract:
Polyhydroxyalkanoates (PHAs) are naturally-occurring biodegradable
thermopolyesters accumulated by bacteria. Copolyester of Poly(3-
hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] were noted for its
high biocompatibility. This makes it an excellent candidate for medical as well
as biopharmaceutical applications. A Gram-negative bacteria, Cupriavidus
sp. USMAA1020 has the ability to synthesized P(3HB-co-4HB) copolymer
with various 4HB monomer compositions. Additional copies of PHA synthase
gene (PhaC) from Cupriavidus sp. USMAA1020 (PhaC1020) and Cupriavidus
sp. USMAA2-4 (PhaC2-4) the key enzyme in PHA synthesis into Cupriavidus
sp. USMAA1020 wild-type strain resulted in higher 4HB monomer
composition of the copolymer produced. The transformant strains was
cultivated with 1,6-hexanediol (0.5175 wt%) and γ-butyrolactone (0.1725
wt%) through one-stage cultivation. 4HB composition up to 93 mol%
obtained by Cupriavidus sp. USMAA1020phaC1020 while 91 mol% 4HB molar
fraction was obtained by Cupriavidus sp. USMAA1020phaC2-4.
