Process method for separating and purifying glutamine

The invention discloses a process for separating and extracting L-glutamine from fermentation liquor. The process comprises the following steps of: carrying out ceramic filtration and microfiltration, decolorizing, adding a reagent I, concentrating, crystallizing, washing crystals, drying and the like. The reagent I is at least one of 3-acetylpyridine, (2, 2, 6, 6-tetramethyl-4-piperidinyl)-1, 3-benzene diamide, 2, 6-di-tert-butylpyridine and N-methyl-N-vinyl acetamide. The reagent I improves the thermal stability and the acid and alkali resistance stability of the L-glutamine. Impurities are not easy to separate out, and the product yield is greatly improved. Meanwhile, the dosage of the reagent I is ppm level, and the reagent I cannot be left in the product. The process does not use an ion exchange step, saves acid and alkali, and reduces wastewater and waste liquid. The product purity is 99.0% or above, and the product yield is 90% or above. The method has a good industrial application prospect. 本发明公开了一种从发