Treatment No. Acid substrate Acid substrate loading every 12 hours Feed molar C/N ratio Culture media
1 Acetic acid, propionic acid, butyric acid 1.5 g/L total at 1:1:1 mass ratio 70 every feeding SWW
2 Acetic acid 1.5 g/L 70 every feeding SWW
3 Acetic acid 1.5 g/L 70 at time 0 h SWW
4 Acetic acid 1.5 g/L 70 at time 0 h SWW+sodium acetate every feeding to buffer acetic acid (equimolar, target pH=pKa=4.76)
5 Acetic acid 1.5 g/L 70 at time 0 h SWW in 5X MOPS buffer set at pH 7.2
6 Acetic acid 3 g/L 140 at time 0 h SWW in 5X MOPS buffer set at pH 7.2
Table 1: Experimental treatment conditions in the fed-batch runs.