The invention relates to a nitrogenous composition resulting from the enzymatic hydrolysis of an aqueous solution of maize gluten, having a ratio of the concentrations or inorganic phosphorus to total phosphorus (Pi/Pt) greater than or equal to 0.05, preferably from 0.05 to 0.5 and a ratio of the concentrations of amine nitrogen to total nitrogen (Na/Nt) greater than or equal to 0.025. The invention also relates to the use of a nitrogenous composition according to the invention in culture media for microorganisms which produce, in particular, organic acid.