Abstract: Disclosed herein is a method of purifying L-glutamic acid by transformation recrystallization which method comprises maintaining crude crystals of L-glutamic acid containing ? crystals of L-glutamic acid in an aqueous solvent at a temperature of from 50° C. to the boiling point of said aqueous solvent in the coexistence of active carbon until about 30% or more of the crystals of L-glutamic acid have been transformed into ? crystals thereof, the amount of said aqueous solvent being an amount not more than the amount sufficient (i.e., an amount insufficient) to form a saturated solution of said crystals of L-glutamic acid, according to which method purified crystals of L-glutamic acid can be obtained extremely rapidly and in high yields, and remarkably conveniently and easily on an industrial scale, as compared with the conventional transformation recrystallization method which is a hitherto common purification method of L-glutamic acid.

Abstract: Disclosed herein is a method of purifying L-glutamic acid by transformation recrystallization which method comprises maintaining crude crystals of L-glutamic acid containing a crystals of L-glutamic acid in an aqueous solvent at a temperature of from 50° C. to the boiling point of said aqueous solvent in the coexistence of active carbon until about 30% or more of the crystals of L-glutamic acid have been transformed into &bgr; crystals thereof, the amount of said aqueous solvent being an amount not more than the amount sufficient (i.e., an amount insufficient) to form a saturated solution of said crystals of L-glutamic acid, according to which method purified crystals of L-glutamic acid can be obtained extremely rapidly and in high yields, and remarkably conveniently and easily on an industrial scale, as compared with the conventional transformation recrystallization method which is a hitherto common purification method of L-glutamic acid.