Preparation method of alpha-ketoglutarate

The invention discloses a preparation method of alpha-ketoglutarate. According to the preparation method, L-glutamic acid or salt of L-glutamic acid is taken as a raw material, specifically, the preparation method comprises the steps that amino groups on L-glutamic acid are removed by adopting L-glutamate deaminase under the condition that the pH is 8.0-9.0 and the temperature is 30-50 DEG C, and then active carbon decoloration and filtering, purification by adopting a cation exchange resin, concentration and crystallizing are carried out to obtain the alpha-ketoglutarate finished product. The preparation method has the advantages that the reaction condition is mild, the production cycle is short, the product concentration and yield are high, the environmental protection pressure is small, and the preparation method is suitable for large-scale industrial production. The cation resin is adopted for separating the residual L-glutamic acid and alpha-ketoglutarate products which are not transformed, so that the y