Fig. 7

Ammonium production in AZBB281 grown under optimized conditions. Shown are the ammonium production (top) and OD₆₀₀ (bottom) of AZBB281 grown under conditions found to produce the most ammonium per unit time. Cultures were grown at 28 °C, with 15 mL culture volumes, in Burk’s medium supplemented with additional nitrogenase cofactor-related elements (B/MoFeS medium), and shaken at 300 rpm. Bottom graph optical density plotted on a log₂-based scale (y-axis). Data points indicate averages, while error bars represent standard deviation (N = 5). All data points (lighter shade) are included for reference