Table 4.
Thermal properties of PHA containing 3H4MV synthesized by the mutant 1F2 using leucine as a 3H4MV precursor, P(3HB-co-3HV), and P(3HB-co-3HHx)
| PHA composition a | Thermal property | Molecular weight | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Polymer | Leucine (g/L) | 3HV (mol%) | 3H4MV (mol%) | 3HHx (mol%) | Total b (mol%) | Tm (°C) | Tg (°C) | ΔHm (J/g) | Mn (×103) | Mw/Mn |
| P(3HB-co-3HV-co-3H4MV)c | 0 | 1.6 | 0.8 | 0 | 2.4 | 146, 159 | 3 | 42 | 250 | 1.9 |
| P(3HB-co-3HV-co-3H4MV)c | 5 | 2.3 | 1.0 | 0 | 3.3 | 142, 154 | 3 | 40 | 251 | 1.8 |
| P(3HB-co-3HV-co-3H4MV)c | 10 | 1.2 | 3.1 | 0 | 4.3 | 137, 151 | 3 | 42 | 98 | 1.6 |
| P(3HB) d | - | 0 | 0 | 0 | 0 | 172 | 4 | 77 | 224 | 2.1 |
| P(3HB-co-3HV) e | - | 8 | 0 | 0 | 8 | 170 | - | 70 | - | - |
| P(3HB-co-3HHx) f | - | 0 | 0 | 5 | 5 | 151 | 0 | 69 | 100 | 1.9 |
Mn, number-average molecular weight; Mw, weight-average molecular weight; Mw/Mn; polydispersity index; Tm, melting temperature; Tg, glass-transition temperature; ΔHm, enthalpy of fusion.
a PHA compositions of purified copolymer samples were determined by GC. Copolymer compositions other than 3HB are shown.
b 3HV plus 3H4MV plus 3HHx fraction.
c PHA synthesized by mutant 1F2 from fructose (20 g/L) and leucine (0, 5, 10 g/L).
d P(3HB) homopolymer synthesized by R. eutropha H16.
e (Scandola et al. 1992).
f (Doi et al. 1995).