EN
In this study, favorable carbon-nitrogen ratio for high yields of gibberellic acid (GA₃) production from Pseudomonas sp. was investigated. First of all, optimum carbon (glucose, maltose, sucrose, fructose, lactose) and nitrogen (KNO₃, NH₄C1, NaNO₃, urea, glycine) sources among the others were chosen. The highest yield of GA₃ productivity was found in growth medium supplemented with fructose (168.5 mg/L). NaNO₃ was found as a suitable nitrogen source (141 mg/L). Then, in order to determine the optimum carbon-nitrogen ratio, different concentrations of carbon (from 50 mM to 150 mM) and nitrogen (from 17 mM to 47 mM) sources were added in culture media. As a result, optimum carbon-nitrogen ratio for GA₃ production from Pseudomonas sp. was found to be 100:17 mM.