Table 3. pH, product and NADH/NAD⁺ ratios of different recombinant strains at initial growth pH of 7.3 after 12 h aerobic culture.

		Concentrations of pyruvate metabolites (mM)
Strains	Final pH	Lactate	Acetate	Diacetyl	Acetoin	NADH/NAD+ ratio
DA	5.93±0.03	23.41±0.11	8.47±0.14	ND	ND	0.741±0.009
DA/pA17nox	6.02±0.04	21.15±0.08	8.40±0.15	1.07±0.03	0.69±0.02	0.711±0.005
DA/pA1nox	6.05±0.02	20.28±0.13	8.43±0.09	1.19±0.01	0.87±0.05	0.689±0.006
DA/pA12nox	6.05±0.05	19.86±0.29	9.26±0.1	1.51±0.03	0.92±0.03	0.681±0.002
DA/pA56nox	6.07±0.02	19.09±0.12	9.12±0.14	1.8±0.01	1.01±0.04	0.556±0.008
DA/pA97nox	6.10±0.01	18.15±0.21	10.29±0.13	1.8±0.04	1.05±0.01	0.55±0.005
DA/pA19nox	6.10±0.01	17.46±0.17	11.08±0.07	1.84±0.05	1.05±0.03	0.541±0.005
DA/pA32nox	6.12±0.02	16.24±0.1	11.96±0.08	2.02±0.04	1.38±0.01	0.462±0.002
DA/pD2nox	6.14±0.04	14.21±0.13	13.11±0.12	2.26±0.02	1.67±0.05	0.457±0.002
DA/pB89nox	6.18±0.01	13.00±0.09	13.42±0.21	2.39±0.06	1.96±0.04	0.413±0.004
DA/pB21nox	6.22±0.02	11.76±0.16	13.09±0.01	3.38±0.12	2.14±0.04	0.406±0.003
DA/pB6nox	6.32±0.03	9.94±0.07	12.34±0.14	4.16±0.06	2.83±0.06	0.383±0.003

ND, not detected. The values are means ± standard deviations for three independent experiments.