Table 2 Comparison between free cell and immobilized cell batch fermentation for butyric acid production with differential operating modes
Fermentation parameter | Free-cell fermentation mode | Immobilized cell fermentation mode | ||
|---|---|---|---|---|
Batch | Fed-batch | Batch | Fed-batch | |
Fermentation time (h) | 30 ± 2 | 107 ± 2 | 24 ± 2 | 85 ± 2 |
Fermentable sugar utilized (g/L) | 43.55 ± 2.17 | 153.47 ± 2.42 | 47.52 ± 2.13 | 150.68 ± 2.51 |
Fermentable sugar utilization rate (g/L·h) | 1.45 ± 0.03 | 1.43 ± 0.04 | 1.98 ± 0.03 | 1.77 ± 0.03 |
Butyrate concentrations (g/L) | 18.48 ± 0.92 | 58.32 ± 3.01 | 21.47 ± 1.07 | 61.87 ± 2.37 |
Butyrate yield (g/g) | 0.42 ± 0.01 | 0.38 ± 0.01 | 0.45 ± 0.01 | 0.42 ± 0.01 |
Butyrate productivity (g/L·h) | 0.62 ± 0.02 | 0.55 ± 0.02 | 0.85 ± 0.03 | 0.73 ± 0.01 |
Acetate concentration (g/L) | 3.46 ± 0.16 | 5.46 ± 0.21 | 2.49 ± 0.17 | 4.23 ± 0.18 |
Butyrate/acetate ratio (g/g) | 5.34 ± 0.23 | 10.68 ± 0.46 | 8.62 ± 0.38 | 14.61 ± 0.57 |