Biosynthesis of polyhydroxyalkanoate (PHA) using waste fish oil by cupriavidus necator H16
| dc.contributor.author | Kaesavan, Puvaneswary | |
| dc.date.accessioned | 2015-05-26T08:05:12Z | |
| dc.date.available | 2015-05-26T08:05:12Z | |
| dc.date.issued | 2014-08 | |
| dc.description.abstract | The potential use of waste fish oil (WFO) as carbon source for production of polyhydroxyalkanoates (PHAs) using Cupriavidus necator H16 was investigated. Small aggregates of the WFO were observed to be floating on the surface of culture medium, which limited the accessibility of the carbon source to the bacterium. An attempt of using Gum Arabic (GA) as an emulsifier was carried out to address the limited availability of WFO. WFO was found to be an effective carbon source for PHA production in the presence of GA at 2.5 g/L. Cell dry weight of 4.85 g/L and P(3HB) content up to 73 wt% were achieved by using 15 g/L of waste fish oil as the carbon source. Characterization of the PHA synthase enzyme showed 161 U/g activity for soluble fraction. Copolymers poly(3-hydroxybutyrate-co-4-hydroxybutyrate), [P(3HB-co-4HB)] and poly(3-hydroxybutyrate-co-3-hydroxyvalerate), [P(3HB-co-3HV)] could be produced by C. necator H16 with respective addition of precursors such as sodium 4-hydroxybutyrate, 1,4-butanediol, γ-butyrolactone, or sodium valerate to the culture medium supplemented with WFO. Up to 63 mol% of 3HV monomer was incorporated into P(3HB-co-3HV) copolymer synthesized by C. necator H16. Among the 4HB precursors tested, γ-butyrolactone was found to be the best precursor for P(3HB-co-4HB) copolymer production. P(3HB-co-4HB) copolymer with 36 mol% of 4HB monomer was produced. The presence of the 3HB, 3HV and 4HB monomers, as well as their composition and randomness in the polymer produced were confirmed using 1H NMR and 13C NMR analyses. The physical and thermal properties of the copolymers were further characterized using gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). P(3HB) and P(3HB-co-3HV) copolymers with a molecular weight range of 1.5 × 106 to 2.0 × 106 were produced. The melting temperature obtained were in the range of 67 to 169 °C for P(3HB), P(3HB-co-3HV) and P(3HB-co-4HB) copolymers. This study has demonstrated the possibility of using WFO as a potential carbon source for cell growth and PHA production | en_US |
| dc.identifier.uri | http://hdl.handle.net/123456789/751 | |
| dc.subject | Polyhydroxyalkanoate | en_US |
| dc.subject | Fish oil | en_US |
| dc.title | Biosynthesis of polyhydroxyalkanoate (PHA) using waste fish oil by cupriavidus necator H16 | en_US |
| dc.type | Thesis | en_US |
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