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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)

From: Enhanced Incorporation of 3-Hydroxy-4-Methylvalerate Unit into Biosynthetic Polyhydroxyalkanoate Using Leucine as a Precursor

   PHA composition a Thermal property Molecular weight
Polymer Leucine (g/L) 3HV (mol%) 3H4MV (mol%) 3HHx (mol%) Total b (mol%) T m (°C) T g (°C) Δ H m (J/g) M n (×10 3 ) M w/M n
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
  1. M n, number-average molecular weight; M w, weight-average molecular weight; M w/M n; polydispersity index; T m, melting temperature; T g, glass-transition temperature; ΔH m, enthalpy of fusion.
  2. a PHA compositions of purified copolymer samples were determined by GC. Copolymer compositions other than 3HB are shown.
  3. b 3HV plus 3H4MV plus 3HHx fraction.
  4. c PHA synthesized by mutant 1F2 from fructose (20 g/L) and leucine (0, 5, 10 g/L).
  5. d P(3HB) homopolymer synthesized by R. eutropha H16.
  6. e (Scandola et al. 1992).
  7. f (Doi et al. 1995).
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