AcademicArticleSCO_85028467918
Overview
abstract
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© 2017 Elsevier B.V. Many heterologous transformation studies have been carried out using the Cupriavidus necator PHB¿4 strain to investigate the expression characteristics of various polyhydroxyalkanoate (PHA) synthase enzymes. In this study, we generated a recombinant C. necator PHB¿4 strain by transforming a plasmid (pMRC03) harbouring the synthetic phaC2 gene of Pseudomonas putida CA-3. Under conditions favourable for expression of the phaC2 P.put CA-3 gene, canola oil was used as carbon source for the synthesis of PHAs. The expressed synthase polymerised monomers of 3-hydroxybutyrate (3-HB), 3-hydroxyvalerate (3-HV) and 3-hydroxyhexanoate (3-HHx) in the recombinant C. necator PHB¿4 (pMRC03) strain. We then co-expressed the phaC2P.put CA-3 gene with the native phaC1C.ne gene in wild type Cupriavidus necator H16 (C. necator H16 (pMRC03)). This co-expression produced a PHA blend of 3-HB, 3-HV, 3-HHx and 3-hydroxyoctanoate (3-HO) monomers in the presence of canola oil. Gas chromatography analysis revealed the presence of 94 mol% 3-HB, 1 mol% 3-HV, 4 mol% 3-HHx and 1 mol% 3-HO in a tetra-polymer. Thus, we confirmed that a synthetic phaC2 gene encoding the synthase enzyme is functionally active with substrates ranging from short to medium chain length PHAs.