Table 5.

Effect of exogenous formate addition on pH of fermentation medium.

Concentration of formate added at 10 h	10 h	24 h	48 h
0 mM	5.64 ± 0.03a	5.81 ± 0.04a	6.14 ± 0.02a
5 mM	5.66 ± 0.05a	5.96 ± 0.04b	6.35 ± 0.04b
10 mM	5.63 ± 0.08a	6.05 ± 0.04c	6.48 ± 0.05c

E. coli MG1655 harboring pTrc99A-P_trc-budAB was grown in LB medium with 5 g/l glucose, 1 mM IPTG, and 100 μg/ml Ap. Formate was added at 10 h and pH was measured at 10, 24, and 48 h. ^a-c pH values with different superscripts in the same column are significantly different (p < 0.05).