Table 3. Measurements of extra-cellular metabolites and biomass production during transition of anaerobic cultures of E. coli MG1655 to micro-aerobic conditions.

Time after transition to micro-aerobic (10 µM O2) conditions (min)	Acetate (mM)	Formate (mM)	Succinate (mM)	Putrescine (mM)	Pyruvate (mM)	Lactate (mM)	Fumarate (mM)	Ethanol (mM)	Biomass (mg cdw ml−1)
0	18.7±2.2	35.1±4.0	5.3±0.9	0.015±0.003	<0.10	0.12±0.03	0.01±0.007	9.7±1.1	0.46±0.04
10	17.7±1.1	32.9±1.5	4.8±0.6	0.023±0.001	0.41±0.10	0.14±0.02	0.07±0.02	9.1±0.4	0.47±0.04
30	16.8±1.2	30.9±2.1	4.3±0.5	0.042±0.013	0.90±0.27	0.18±0.02	0.18±0.02	8.5±0.5	0.52±0.06
60	15.3±1.1	26.6±2.1	3.4±0.3	0.043±0.003	0.99±0.39	0.18±0.04	0.25±0.04	6.9±1.0	0.54±0.07
120	16.6±0.7	22.6±0.9	2.3±0.1	0.055±0.010	0.23±0.31	0.14±0.03	0.32±0.04	6.5±0.7	0.65±0.06

Metabolites were quantified by NMR as described in Materials and Methods section. The values are the means from four independent cultures ±standard deviation. The errors for the pyruvate data were relative large and therefore a t-test analysis was performed which showed the 0–10 min (p = 0.053), the 10–30 min (p = 0.004), 60–120 min (p = 0.009) but not the 30–60 min (p = 0.828) were significantly different.