NOVELTY - Closed recirculation extraction of glutamic acid with transitional crystal comprises crystallizing glutamic acid fermentation liquor; separating isoelectric mother liquor to obtain ~a-glutamic acid crystal; evaporating the mother liquor to desalt and precipitate ammonium sulfate; adding water or monosodium glutamate mother liquor and cooling to precipitate the glutamic acid to ~b-crystal which is a transitional crystal; mixing a condensed liquid of transitional crystal mother liquor with the desalted and condensed mother liquor; and separating the solid filtrated residue.    USE - Method for the closed recirculation extraction of glutamic acid with transitional crystal.    ADVANTAGE - The extraction rate of the glutamic acid is high, and the obtained glutamic acid crystal has excellent quality. The recirculation extraction method obtains byproducts including bacteria protein, ammonium sulfate, and humus, thus eliminating pollution of high density waste water.    DETAILED DESCRIPTION - Closed recirculation extraction of glutamic acid with transitional crystal comprises crystallizing glutamic acid fermentation liquor using water at 30?oC, 0-60 vol.% monosodium glutamate mother liquor, hydrolyzing liquid or industrial heavy vitriol to adjust the pH at 3-3.2, at 5-15?oC to precipitate alpha crystal; carrying out a first separation for the isoelectric mother liquor to obtain 0-85% ~a-glutamic acid crystal, and a second separation to completely separate the left glutamic acid crystal and isoelectric mother liquor; separating the isoelectric mother liquor to obtain bacteria protein and clear mother liquor; heating the clear mother liquor to evaporate and condense for 2-5 times, at 0.01-0.1 MPa and 45-121?oC; evaporating the mother liquor to desalt and enable the ammonium sulfate to be precipitated from the condensed mother liquor, at 0.01-0.1 MPa and 45-121?oC; adding 2-5 times weight rate water or monosodium glutamate mother liquor to the ~a-glutamic acid crystal, adjusting the pH using lye at 4-6 at 70-90?oC to dissolve the glutamic acid, and cooling to 5-30?oC to precipitate the glutamic acid to ~b- crystal which is called transitional crystal; separating to obtain ~b-glutamic acid crystal, and discharging transitional crystal mother liquor; heating the transitional crystal at 0.01-0.1 MPa and 55-121?oC, and condensing the transitional crystal mother liquor for 2-8 times; mixing the condensed liquid of transitional crystal mother liquor with the desalted and condensed mother liquor, and adding vitriol at a weight ratio of 0.2-1:1, at 80-150?oC for 1-5 hours; and cooling to 30-80?oC, and separating the solid filtrated residue and the hydrolyzing liquid.    DESCRIPTION OF DRAWING(S) - The drawing is a flow chart of the method for closed recirculation extraction of glutamic acid with transitional crystal.