Abstract: A method for producing L-glutamic acid by fermentation, which comprises culturing a microorganism having L-glutamic acid-producing ability in a liquid medium of which pH is adjusted to a condition under which L-glutamic acid produced by the microorganism is allowed to be precipitated, to allow L-glutamic acid to be produced and accumulated with precipitation of L-glutamic acid accompanied, wherein an operation causing existence of L-glutamic acid crystals in the medium is performed when a concentration of L-glutamic acid in the medium is lower than the concentration at which spontaneous crystallization occurs.

Abstract: An organic nitrogen-containing composition comprising fermentation mother liquor obtained by culturing a microorganism having L-glutamic acid-producing ability in a liquid medium of which pH is adjusted to a condition under which L-glutamic acid is allowed to be precipitated, to allow L-glutamic acid to be produced and accumulated with precipitation of L-glutamic acid accompanied, and then separating L-glutamic acid from the medium.

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.

Abstract: A method for producing L-glutamic acid by fermentation, which comprises culturing a microorganism having L-glutamic acid-producing ability in a liquid medium of which pH is adjusted to a condition under which L-glutamic acid produced by the microorganism is allowed to be precipitated, to allow L-glutamic acid to be produced and accumulated with precipitation of L-glutamic acid accompanied, wherein an operation causing existence of L-glutamic acid crystals in the medium is performed when a concentration of L-glutamic acid in the medium is lower than the concentration at which spontaneous crystallization occurs.

Abstract: An organic nitrogen-containing composition comprising fermentation mother liquor obtained by culturing a microorganism having L-glutamic acid-producing ability in a liquid medium of which pH is adjusted to a condition under which L-glutamic acid is allowed to be precipitated, to allow L-glutamic acid to be produced and accumulated with precipitation of L-glutamic acid accompanied, and then separating L-glutamic acid from the medium.

Abstract: A process for producing an alkali metal polyphosphate, comprising heating a solution comprising a solvent, alkali metal ions, phosphate ions, and 3 to 50% by weight of organic matter, wherein the solution contains, in total, 5 to 65% by weight of the alkali metal ions and the phosphate ions, and the ratio M/P is 1.0 to 3.0, wherein M is the number of moles of alkali metal ions in the solution and P is the number of moles of orthophosphate ions in the solution, at a temperature of 800.degree. to 1200.degree. C. in the presence of excess air, optionally after the solution is at least partially dried to solid, to produce the alkali metal polyphosphate.

Abstract: A method for producing L-glutamic acid by fermentation, which comprises culturing a microorganism having L-glutamic acid-producing ability in a liquid medium of which pH is adjusted to a condition under which L-glutamic acid produced by the microorganism is allowed to be precipitated, to allow L-glutamic acid to be produced and accumulated with precipitation of L-glutamic acid accompanied, wherein an operation causing existence of L-glutamic acid crystals in the medium is performed when a concentration of L-glutamic acid in the medium is lower than the concentration at which spontaneous crystallization occurs.