Table 3.
Yield and molar conversion of the vanillic acid and vanillin from the fermentation of PP and PCL liquor in two different feeding modes (n = 3)
| Product | Small volume feeding | Large volume feeding | ||||
|---|---|---|---|---|---|---|
| PP liquor | PCL liquor | PP liquor | PCL liquor | |||
| Ferulic acid | Feed (μmol) | 33 ± 5 | 10.1 ± 0.7 | 109 ± 17 | 34 ± 2 | |
| Consumed (μmol) | 33 | 10.1 | 48 | 18.4 | ||
| Remained | mg L−1 | n/d | n/d | 117 ± 10 | 30 ± 1 | |
| μmol | < 0.00 | < 0.00 | 60 ± 5 | 15.4 ± 0.5 | ||
| Vanillic acid | Yielda | mg L−1 | 4 ± 2 | 0.9 ± 0.1 | 7 ± 2 | 6 ± 1 |
| μmol | 2.6 ± 0.9 | 0.52 ± 0.07 | 3.8 ± 0.9 | 3.8 ± 0.7 | ||
| Molar conversion (%)b | 7.9 | 5.1 | 7.9 | 20.7 | ||
| Vanillin | Yielda | mg L−1 | n/d | 0.8 ± 0.1 | 5 ± 1 | 2.5 ± 0.2 |
| μmol | n/d | 0.51 ± 0.06 | 3 ± 0.8 | 1.6 ± 0.2 | ||
| Molar conversion (%)b | n/d | 0.5 | 6.3 | 8.9 | ||
n/d not detected
aYield indicates the concentration (mg L−1) of vanillic acid/vanillin produced from A. niger fermentation
bMolar conversion indicates the percentage of vanillic acid/vanillin molar yield produced from the molar consumption of ferulic acid during A. niger fermentation