US 5,329,014 AGranted

Method for recovering optically active tryptophan

AssigneeAjinomoto Co., Inc.

InventorsToru Shinohara, Masaru Otani

Life of this patent

Estimating the term…

Loading patent…

Abstract

Optically active tryptophan of high purity can be obtained in high yields from a tryptophan fermentation broth, using crystallization of optically active tryptophan hydrochloride in combination with concurrent neutralization crystallization. According to the present invention, optically active tryptophan from a tryptophan containing fermentation broth, is carried out by (a) removing cells from the fermentation broth, adding hydrochloric acid, or a mixture of hydrochloric acid and an inorganic salt which contains chloride ions, to the cell-free broth to effect crystallization, (b) separating optically active tryptophan hydrochloride, (c) dissolving the optically active tryptophan hydrochloride, and (d) subjecting the resulting solution and an alkali solution to concurrent neutralization crystallization, maintaining a pH of the crystallization solution in the range of from 3 to 8.

Claims6

Dependent claims

A method for recovering optically active tryptophan from a fermentation broth comprising optically active tryptophan, which comprises:

(i) removing cells from said fermentation broth comprising optically active tryptophan to obtain a cell-free fermentation broth comprising optically active tryptophan and proteins;
(ii) adding (a) hydrochloric acid or (b) a mixture of hydrochloric acid and an inorganic salt containing chloride ion to said cell-free fermentation broth obtained in step (i) to precipitate and separate optically active tryptophan hydrochloride from said cell-free fermentation broth and to obtain separated optically active tryptophan hydrochloride;
(iii) dissolving said separated optically active tryptophan hydrochloride, to obtain a solution comprising said optically active tryptophan hydrochloride;
(iv) subjecting said solution comprising said optically active tryptophan hydrochloride to concurrent neutralization crystallization by simultaneously adding said solution of optically active tryptophan hydrochloride and an alkali solution, into a crystallizer while maintaining the pH in a range of from 3 to 8;
and
(v) isolating optically active tryptophan crystals thereof.

3 more elements

Dependencies are inferred from the claim text.