Table 2.
Initial ethanol and acetic acid concentrations, ethanol production and cell viability during repeated batches with encapsulated T18
| Batch | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | |
| A | ||||||||||
| Cell Viability (%) | 100 | 97 | 98 | 97 | 98 | 98 | 98 | 98 | 97 | 98 |
| [EtOH]0 (g/L) | 0 | 5.0 | 4.8 | 6.5 | 6.6 | 5.9 | 5.6 | 5.5 | 6.0 | 5.8 |
| [HAc]0 (g/L) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| [EtOH] (g/L) | 16.6 | 21.4 | 24.2 | 21.2 | 20.9 | 24.6 | 20.8 | 23.3 | 23.4 | 24.7 |
| QP (g/L/h) | 4.2 | 4.1 | 4.7 | 4.2 | 4.1 | 4.7 | 4.3 | 4.5 | 4.4 | 4.6 |
| B | ||||||||||
| Cell viability (%) | 99 | 98 | 98 | 98 | 97 | 98 | 98 | 97 | 96 | 92 |
| [EtOH]0 (g/L) | 0 | 4.8 | 6.1 | 6.9 | 6.3 | 7.0 | 7.1 | 6.4 | 7.6 | 6.7 |
| [HAc]0 (g/L) | 4.3 | 7.7 | 9.6 | 8.3 | 10.4 | 10.3 | 9.7 | 10.3 | 10.7 | 10.7 |
| [EtOH] (g/L) | 16.1 | 22.7 | 23.8 | 25.0 | 24.6 | 25.8 | 25.6 | 26.8 | 27.5 | 27.8 |
| QP (g/L/h) | 1.6 | 1.8 | 1.6 | 1.8 | 1.8 | 1.9 | 1.7 | 1.9 | 1.8 | 1.9 |
| C | ||||||||||
| Cell viability (%) | 99 | 98 | 98 | 98 | 98 | 98 | 98 | 84 | 81 | 72 |
| [EtOH]0 (g/L) | 0 | 4.1 | 6.0 | 6.1 | 5.9 | 5.8 | 5.8 | 5.4 | 6.0 | 6.1 |
| [HAc]0 (g/L) | 7.9 | 11.7 | 13.3 | 13.2 | 14.0 | 14.0 | 14.4 | 14.2 | 14.4 | 14.8 |
| [EtOH] (g/L) | 15.8 | 22.4 | 23.8 | 23.7 | 23.2 | 22.9 | 23.3 | 24.0 | 24.0 | 24.6 |
| QP (g/L/h) | 1.6 | 1.7 | 1.6 | 1.8 | 1.4 | 1.4 | 1.5 | 1.5 | 1.3 | 1.6 |
| D | ||||||||||
| Cell viability (%) | 99 | 98 | 98 | 98 | 98 | 98 | 90 | 80 | 66 | 61 |
| [EtOH]0 (g/L) | 0 | 3.7 | 6.4 | 6.2 | 5.6 | 5.7 | 5.3 | 4.5 | 5.8 | 6.0 |
| [HAc]0 (g/L) | 10.7 | 13.9 | 15.5 | 16.9 | 17.7 | 17.7 | 17.3 | 18.9 | 17.9 | 17.1 |
| [EtOH] (g/L) | 14.2 | 15.9 | 15.2 | 15.9 | 15.5 | 15.5 | 15.3 | 16.7 | 13.7 | 14.7 |
| QP (g/L/h) | 1.2 | 1.3 | 1.4 | 1.3 | 1.2 | 1.1 | 1.0 | 0.7 | 0.4 | 0.3 |
Final cell viability and initial ethanol and acetic acid concentrations in repeated batch fermentations with encapsulated T18 in YPX 40 g/L with different acetic acid concentrations: A—0 g/L; B—4 g/L; C—8 g/L and D—10 g/L (35 °C, DO0 = 100, 50 gdrycells/L, 150 rpm and pH 5.2). Values are triplicates averages, with less than 5% standard error. [EtOH]0 and [HAc]0 correspond to initial accumulated ethanol and acetic acid concentrations, respectively; [EtOH] is the final ethanol concentration and QP is ethanol productivity