Biosynthesis of P(3HB-co-3HV-co-3HHp) terpolymer by Cupriavidus necator PHB4 transformant harboring the highly active PHA synthase gene of Chromobacterium sp. USM2

ABSTRACT

Aims: This study evaluates potentials of Cupriavidus necator PHB4 transformant harboring the highly active polyhydroxyalkanoate synthase gene (phaC) of a locally isolated Chromobacterium sp. USM2 for its ability to incorporate 3-hydroxyheptanoate (3HHp) monomer. Methodology and results: A mixture of fructose and sodium heptanoate fed to the culture gave rise to poly(3- hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyheptanoate), [P(3HB-co-3HV-co-3HHp)] terpolymer synthesis, with traces of 3HHp monomers confirmed through gas chromatography (GC), proton (1H) and carbon (13C) NMR spectra. Conclusion, significance and impact of study This study has revealed that the PHA synthase of Chromobacterium sp. USM2 has a broad range of substrate specificity. The synthase is able to polymerize 3-hydroxyalkanoate monomers having 4–7 carbon atoms.