Table 3.
NMR and DSC characterization of PHB produced by C. necator ATCC 17697 and comparison with PHB produced by other microorganisms.
| This work | Ref. [64] | Ref. [66] | Ref. [65] | Ref. [67] | ||||
|---|---|---|---|---|---|---|---|---|
| Bacterial strain | Cupriavidus necator | Cupriavidus necator | Cyanobacteria |
Bacillus cereus |
Cupriavidus necator | Bacillus megaterium | Standard PHB | |
| ATCC 17697 | DSM 545 | spp. | SPV | MTCC 8320 | MTCC 453 | |||
| Carbon source | fructose | glucose | glucose | glucose | fructose | fructose | ||
| Extraction method | solvent |
solvent |
solvent |
solvent |
solvent and ultrasonication |
solvent and ultrasonication |
||
| DSC analysis | ||||||||
| Tg (°C) | 3.5 | 6 | 6 | 2 | 6 | 6 | –8 | |
| Tm (°C) | 165.4 | 180 | 171 | 169.7 | 175 | 176 | 176 | |
| Tc (°C) | 54.3 | - | 78.8 | - | 84 | 104 | 90 | |
| Xc (%) | 56.0 |
64.6 |
56.8 |
57.7 |
44 |
23 |
- |
|
| NMR spectra (chemical shift in ppm) | ||||||||
| 13C NMR spectrum | -CH3 | 19.9 | - | - | 21.2 | 19.95 | 19.95 | 19.95 |
| -CH2- | 40.1 | - | - | 42.7 | 40.99 31.09 |
40.99 31.09 |
40.99 31.09 |
|
| -CH- | 67.7 | - | - | 68.5 | 67.81 | 67.80 | 67.81 | |
| -CO- | 169.3 | - | - | 169.7 | 169.32 | 169.32 | 169.32 | |
| 1H NMR spectrum | -CH- (m) | 5.26 | - | 5.22–5.28 | - | 5.26 | 5.26 | 5.26 |
| -CH2- (dq) | 2.45–2.63 | - | 2.43–2.64 | - | 2.17–2.60 | 2.17–2.62 | 2.17–2.60 | |
| -CH3 (d) | 1.27 | - | 1.27–1.29 | - | 1.28–1.60 | 1.26 | 1.28 | |
m: multiplet, dq:double quadruplet, d: doublet.