TABLE 3.
Solvent extraction of PHB from Z. denitrificans MW1 cellsa
| Solvent (temp) | Time (h) | Amt of extracted PHB (g/50 ml solvent) | Recovery (%) | Purity (%) |
|---|---|---|---|---|
| Chloroform (24°C) | 24 | 1.82 ± 0.04 | 54.5 ± 0.06 | ND |
| 48 | 1.84 ± 0.04 | 55.4 ± 0.06 | ND | |
| 72 | 1.85 ± 0.06 | 55.6 ± 0.06 | 97.6 ± 2.1 | |
| 228 | 1.81 ± 0.03 | 54.4 ± 0.06 | 96.8 ± 1.8 | |
| Chloroform (30°C) | 24 | 2.47 ± 0.10 | 74.2 ± 0.09 | ND |
| 48 | 2.81 ± 0.03 | 84.3 ± 0.10 | ND | |
| 72 | 2.83 ± 0.13 | 85.0 ± 0.10 | 98.3 ± 1.3 | |
| 96 | 2.82 ± 0.12 | 84.7 ± 0.10 | ND | |
| 120 | 2.72 ± 0.21 | 81.7 ± 0.09 | 97.9 ± 0.8 | |
| Chloroform (41°C) | 24 | 2.19 ± 0.05 | 65.9 ± 0.08 | 94.2 ± 2.5 |
| Methylene chloride (24°C) | 24 | 1.09 ± 0.03 | 32.6 ± 0.04 | ND |
| 48 | 1.13 ± 0.03 | 34.1 ± 0.04 | ND | |
| 72 | 1.21 ± 0.10 | 36.2 ± 0.04 | 98.8 ± 1.0 | |
| 228 | 1.05 ± 0.03 | 31.5 ± 0.04 | 96.4 ± 2.7 |
Lyophilized cells of Z. denitrificans MW1 (100-g portion) from fed-batch fermentation 4 (66.9% ± 7.6% PHB [wt/wt]) were stirred into 10 volumes of solvent at different extraction temperatures. Fifty-milliliter sample portions were withdrawn at the indicated times. Samples were separated in separation funnels overnight at room temperature. Clear PHB-solvent solutions were withdrawn and concentrated. Afterwards, 4 volumes of methanol was added to precipitate PHB, which was then filtered and dried under vacuum. Recovery and purity of PHB were analyzed by GC. Analyses were done in triplicate, and averages and standard deviations for three different analyses are presented. ND, not determined.