Ammonium Hydroxide → L-Methionine

Colonies from agar plates were aseptically transferred into 250 mL flasks containing 30 ml of nutrient broth (DIFCO) and allowed to grow at 30° C. After 24 hours of growth, these microorganisms were used as seed culture in a 3-L fermenter containing growth media consisting of 50 g/L glucose, 50 g/L soy protein hydrolyzate, 1 g/L K2HPO4, 45 g/L (NH4)2SO4, 400 mg/L MgSO4.7H2O, 10 mg/L MnSO4.4H2O, 0.2 mg/L thiamin HCl and 0.05 mg/L biotin. Fermentation was carried out at 31° C. under vigorous agitation and good aeration. pH was maintained at 7.45 during fermentation by addition of ammonium hydroxide (NH4OH). The organisms grew quite well under these conditions with a typical optical density (as measured as OD600) in the range of 25 to 30 after only 24 hours. Fermentation batches were terminated once the initial glucose charge was consumed. The residual L-methionine produced during these fermentations was supplemented with additional L-methionine as described in the Examples below.