TABLE 1.
PHB production by Zobellella denitrificans MW1 in fed-batch fermentationsa
| Fed-batch fermentation no. | Initial vol (liters) | Final vol (liters) | Cultivation time (h) | Amt of glycerol (g) | Residual amt of glycerol (g) | CDW (g/liter) | % PHA (wt/wt) | PHA concn (g/liter) | PHB productivity (g/liter/h) | Yield (g PHB/g glycerol) |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 24 | 36 | 24 | 4,059 | 768 | 29.9 ± 1.3 | 31.0 ± 4.2 | 9.3 ± 1.7 | 0.39 ± 0.07 | 0.10 ± 0.02 |
| 2 (NaCl) | 20 | 26 | 36 | 2,100 | 360 | 32.8 ± 0.6 | 52.0 ± 1.4 | 17.1 ± 0.8 | 0.47 ± 0.02 | 0.26 ± 0.01 |
| 3 (NaCl) | 20 | 33 | 63 | 5,725 | 250 | 63.9 ± 2.0 | 56.0 ± 0.7 | 35.8 ± 1.6 | 0.57 ± 0.02 | 0.22 ± 0.01 |
| 4 (NaCl) | 20 | 30 | 50 | 8,400 | 1,884 | 81.2 ± 2.5 | 66.9 ± 7.6 | 54.3 ± 7.9 | 1.09 ± 0.16 | 0.25 ± 0.04 |
a
Fed-batch fermentations were done by cultivating Z. denitrificans MW1 in a 42-liter Biostat UD-30 stainless steel reactor. Medium components, feeding solutions, and cultivation conditions were as described in the text. All fermentations were operated at 41°C. Fed-batch fermentations 2, 3, and 4 were supplied with 20 g/liter NaCl. Analyses were done in triplicate, and averages and standard deviations are presented.