TABLE 2.

Accumulation of nitrite in the growth medium and the whole-cell nitrate reduction activities of different strains grown under microaerobic conditions^a

Strain	Nitrite accumulation (mM [±SD])	Activity (nmol of nitrate min−1 mg−1 of protein [±SD])
WT	13 ± 2	26 ± 0.2
TW01	0	0
TW01(pNAP01)	12 ± 3	30 ± 12

^aThe culture medium contained 16 mM NO₃⁻. Cells were harvested after 16 h of growth. The whole-cell assay was carried out in a 15-ml serum bottle with a 5-ml cell suspension in TSB. Anaerobic conditions were created by flushing and filling the bottle with argon gas, and the reaction was started by adding 5 mM KNO₃.