# US 4,399,304 A · L-phenylalanine 1/2 sulfate and its use

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- Number: US 4,399,304 A
- Document ID: US4399304A
- Status: Granted
- Kind: A
- Application number: 06/291,914
- Filed: 1981-08-11
- Granted: 1983-08-16
- Earliest claimed: 1979-12-05
- Assignees: Ajinomoto Co., Inc.
- Inventors: Tsutomu Matsuishi; Hiromasa Maruyama; Toshio Kitahara; Akemi Kabashima; Ryuta Toyomasu
- Web page: https://patentgrep.com/patent/US4399304A

## CPC

- C12P 13/222: {Phenylalanine}
- C12P: FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE {(brewing of beer C12C; producing vinegar C12J; producing specific peptides or proteins C07K; producing enzymes C12N9/00; DNA or RNA concerning genetic engineering, vectors, e.g. plasmids, or their isolation, preparation or purification C12N15/00; measuring or testing processes involving enzymes or microorganisms C12Q; measuring or testing processes involving nucleic acid amplification reactions C12Q1/6844; fermentation processes to form a food composition, A21 or A23; compounds in general, see the relevant compound class, e.g. C01, C07)}

## Abstract

The present invention relates to L-phenylalanine 1/2 sulfate and its use in the purification of L-phenylalanine from fermentation broths. When the salt is crystallized from a fermentation broth of L-phenylalanine or a solution produced during an intermediate process of recovering L-phenylalanine from the fermentation broth, impurities derived from the fermentation broth are easily removed.

## Claims

### Claim 1

A process for recovering L-phenylalanine from a fermentation broth containing L-phenylalanine, which comprises adjusting the molar ratio of sulfate ion to L-phenylalanine to greater than 0.5, forming L-phenylalanine 1/2 sulfate in solution and recovering L-phenylalanine crystals from said fermentation broth or from a solution thereof produced during said recovery process.

### Claim 2 (depends on 1)

The process of claim 1, wherein said L-phenylalanine 1/2 sulfate has a half molecule of water of crystallization.

### Claim 3 (depends on 1, 2)

The process of claim 1 or claim 2, wherein said fermentation broth or said solution produced during said process of recovering L-phenylalanine contains L-tyrosine.

### Claim 4 (depends on 1, 2, 3)

The process of claim 1, 2 or claim 3, wherein said process of recovering L-phenylalanine crystals from a L-phenylalanine solution containing sodium sulfate comprises using separation techniques of crystallization, ion-exchange, eluting, cooling, neutralization, decolorization, saturation, heating, washing, filtering, drying or combinations thereof.

### Claim 5 (depends on 4)

The process of claim 4, wherein said sodium sulfate is produced by contacting said L-phenylalanine 1/2 sulfate with sodium hydroxide or a sodium salt capable of producing sodium sulfate by contacting with said L-phenylalanine 1/2 sulfate.

### Claim 6 (depends on 4)

The process of claim 4, wherein the concentration of said sodium sulfate is higher than 10 g/100 g water.