Table 2.
Material properties of the PHB obtained from the Synechocystis Δgdc mutant.
| Source of PHB | Thermal property | Mechanical propertyd | Molecular weight | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Tm (°C) | Tg (°C) | Tcc (°C) | ∆Hm (J/g) | Xc (%) | Elongation at break (%) | Tensile strength (MPa) | Young’s modulus (MPa) | Mw (kDa) | Mn (kDa) | Mw/Mn | |
| Commercial PHBa | 175.4 (159) | 3.5 | 48 | 99 | 68 | 5.8 ± 1.1 | 24 ± 3 | 820 ± 300 | 970 | 330 | 2.9 |
| Calothrix scytonemicola b | 170.7 (164) | 4.1 | 47 | 88 | 60 | 4.2 ± 1.6 | 38 ± 7 | 724 ± 284 | 415 | 196 | 2.1 |
| Synechocystis Δgdc c | 170.4 (163) | 6.7 | 53 | 90 | 62 | 3.8 ± 1.9 | 28 ± 7 | 701 ± 255 | 586 | 234 | 2.5 |
Tm, melting temperature (first melting peak shown in parentheses); Tg, glass-transition temperature; Tcc, cold-crystallization temperature; ∆Hm, enthalpy of fusion; Xc, % crystallinity; Mw, weight-average molecular weight; Mn, number-average molecular weight; Mw/Mn, polydispersity.
aHeterotrophic bacterial PHB. Data are from Sigma-Aldrich (USA).
bPhotoautotrophic cyanobacterial PHB8.
cPhotoautotrophic cyanobacterial PHB. Cells were cultured under normal growth condition for 21 d (this study).
dMechanical properties are the mean ± 1 SD of three independent experiments.