FIG 2.

The nitrate reduction of the wild-type strain of S. loihica PV-4, the in-frame deletion mutants Δcrp1, Δcrp2, ΔnirK, and the Δcrp1 ΔnirK double mutant under low carbon/nitrogen ratios. The concentrations of NO₃⁻ (a), NO₂⁻ (b), NH₄⁺ (c), NO (d), and N₂O (e) in the medium were measured under low carbon/nitrogen ratios (C/N = 2). Lactate (1.66 mM) and nitrate (2 mM) were added to phosphate-buffered basal salt medium supplemented with 0.5 mM ammonium chloride as a nitrogen source.