Table 4.
Vanillic acid yield and its molar conversion during the fermentation of ferulic acid standard solution and liquors of pineapple residues (PP and PCL) (n = 3)
| Substrate | Yield (mg L−1)a | Molar conversion (%)b |
|---|---|---|
| Small volume feeding | ||
| 300 mg L−1 ferulic acid | < 0.00 | 0 |
| PCL liquor | 0.9 ± 0.1 | 5.1 |
| 1000 mg L−1 ferulic acid | 5.8 ± 0.7 | 11.2 |
| PP liquor | 4 ± 2 | 7.9 |
| Large volume feeding | ||
| 300 mg L−1 ferulic acid | 3.9 ± 0.7 | 8.2 |
| PCL liquor | 6 ± 1 | 20.7 |
| 1000 mg L−1 ferulic acid | 15 ± 2 | 11.2 |
| PP liquor | 7 ± 2 | 7.9 |
aYield indicates the concentration (mg L−1) of vanillic acid/vanillin produced after 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