Table 1.

Effect of weak acids on the length of the lag phase and the maximum apparent specific growth rate at pH 5 under aerobic conditions. The results were calculated from at least three biological replicates, and are given as the mean values ± standard deviation. N/A: not available.

	Reference	Acetic acid	Formic acid	Levulinic acid	Cinnamic acid
Parameter	(no stress)	(300 mM)	(220 mM)	(400 mM)	(0.8 mM)
pKa	N/A	4.79	3.75	4.66	4.44
log Pa	N/A	−0.17	−0.54	−0.49	2.13
Undissociated acid (mM)	0	114.4	12.2	121.6	0.17
Lag phase Glu (h)	0	26	4	44	0
μmax-glu (h−1)	0.26 ± 0.00	0.07 ± 0.01	0.11 ± 0.01	0.09 ± 0.01	0.04 ± 0.01
Y X/S (g DCW·g –1 glu)	0.12 ± 0.01	0.06 ± 0.01	0.07 ± 0.01	0.06 ± 0.01	0.05 ± 0.01
Lag phase Eth (h)	0	60	40	75	N/A
μmax-eth (h−1)	0.10 ± 0.01	0.03 ± 0.01b	0.06 ± 0.00	0.01 ± 0.00	N/A

^aThe lipophilic tendency given by the partition coefficient octanol–water (P).

^bGrowth with consumption of ethanol and acetic acid.