FIELD: biotechnology.
SUBSTANCE: invention relates to a method for the separation and purification of a methionine hydroxy analog synthesized by the hydrolysis of 2-hydroxy-4-(methylthio)butanenitrile. Method is characterized by the following technological stages: 1) neutralization of hydrolyzate, containing a hydroxy analogue of methionine, ammonium sulphate and ammonium bisulphate obtained by hydrolysis of 2-hydroxy-4-(methylthio)butanenitrile in the presence of sulphuric acid, with ammonia for the conversion of ammonium bisulphate that contains in the system to ammonium sulphate, its supersaturation and precipitation, followed by phase separation to obtain an organic layer I and an aqueous layer I containing solid ammonium sulphate; 2) the concentration of the organic layer I to remove water and the precipitation of solid ammonium sulphate, separation into solid and liquid phases, attenuating of the derived liquid with water to produce the methionine hydroxy analog of commercial class, storage of the derived solid ammonium sulphate for further use; 3) stirring the aqueous layer I containing solid ammonium sulphate with solid ammonium sulphate obtained in step 2), phase separation to produce an organic layer II and an aqueous layer II containing solid ammonium sulphate; 4) separation into solid and liquid phases of aqueous layer II containing solid ammonium sulphate, drying the derived solid fraction to obtain commercial grade ammonium sulphate. Hydrolysis of 2-hydroxy-4-(methylthio)butanenitrile in the presence of sulphuric acid involves two sub-steps. In the first sub-step, an aqueous solution of sulphuric acid with a concentration of 65–85 % by weight, on the second sub-step – an aqueous solution of sulphuric acid with a concentration of 40–50 % by weight, and the phase separation in step 1) is carried out in the temperature range 30–100 °C.
EFFECT: proposed method makes it possible to obtain a high-quality methionine hydroxy analog with good yield, as well as technical grade ammonium sulphate and does not require the use of an organic solvent.
9 cl, 1 dwg, 6 ex, 2 tbl
