. 2014 Aug 6;5:404. doi: 10.3389/fmicb.2014.00404

Table 2.

Growth of WT and norZ_ch mutant strains of S. wittichii RW1 at variable NaNO₂ and O₂ concentrations.

Variable in growth condition	Doubling time (h)		Yield (OD600 nm)
	WT	*norZ_ch*	WT	*norZ_ch*
Atmospheric O₂, no NaNO₂	5.3^a ^b ^c	4.4^c	0.98^a ^b	0.98^b
Reduced O₂, no NaNO₂	8.2^a	N.D.	0.25^a	N.D.
Atmospheric O₂, 0.3 mM NaNO₂	5.6^a ^b ^c	4.4^c	0.90^a ^b	0.91^b
Reduced O₂, 0.3 mM NaNO₂	8.5^a	N.D.	0.25^a	N.D.
Atmospheric O₂, 1.0 mM NaNO₂	5.5^a ^b ^c	4.4^c	0.82^a ^b	0.84^b
Reduced O₂, 1.0 mM NaNO₂	8.4^a	N.D.	0.22^a ^b	N.D.

Doubling times were calculated during exponential growth from 12 to 20 h. Final cell yields were reported at 32 and 20 h growth when initiated at atmospheric (ca. 22%) and reduced (ca. 3%) O₂ levels, respectively. Values represent averages from 5 separate experiments. Statistically significant differences between groups were determined by Student's t-test at p < 0.05 and are designated as follows:

Significant difference between atmospheric and reduced O₂ for wildtype (WT) cultures only.

Significant difference between WT or norZ_ch mutant cultures incubated with NaNO₂ relative to unamended controls.

Significant difference between WT and norZ_ch mutant cultures grown under identical conditions. N.D., not determined.