Table 4.
Comparison of fed-batch and chemostat cultivations. µ/D: values in percent relative to the maximum specific growth rate µ [h-1]. For control run A and B a range is given due to a constant feeding profile. qs [g*g-1*h-1]: Values in percent relative to the maximum specific substrate uptake rate. For control run A and B at the beginning of the constant feeding profile is given. Specific productivity (qp) [g*g-1*h-1]: Values are normalized to the achieved specific product formation rate in control run A at the end of the fermentation. The depicted values are the average for the whole process as soon as constant process conditions had been achieved. Space-time yield (STY) [g*L-1*h-1]: Values are the overall STY for the total process duration for fed-batch and the average in the constant phase for chemostats. All values are normalized to the achieved STY in control run A
| Fed-batch cultivations | Continuous cultivations | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| control run A | control run B | Screening 1 | Screening 2 | Chemostat 1 | Chemostat 2 | Chemostat 3 | Chemostat 4 | Chemostat 5 | Chemostat 6 | |
| µ/D [%] | 16 – 8 | 15 - 9 | 48 | 18 | 24 | 39 | 72 | 19 | 49 | 57 |
| Process time for calculation [h] | 50 - 81 | 50 - 81 | 25 - 38 | 25 - 55 | 33 - 218 | 32 - 217 | 199 - 295 | 56 - 218 | 49 - 217 | 141 - 295 |
| qs [%] | 12* | 12* | 48 +/- 1 | 18 +/- 2 | 32 +/- 7 | 50 +/- 4 | 98 +/- 5 | 25 +/- 2 | 60 +/-3 | 78 +/- 6 |
| qp [%] | 95 +/- 21 | 83 +/- 59 | 119 +/- 31 | 141 +/- 22 | 56 +/- 56 | 69 +/- 17 | 0 | 29 +/- 32 | 43 +/- 19 | 2.5 +/- 5 |
| STY [%] | 94 | 84 | 80 | 131 | 30 +/- 22 | 46 +/- 11 | 0 | 21 +/- 16 | 33 +/- 10 | 2 +/- 3 |