Chemistry: molecular biology and microbiology – Micro-organism – tissue cell culture or enzyme using process... – Preparing alpha or beta amino acid or substituted amino acid...
Patent
1996-08-08
1998-04-21
Lankford, Jr., Leon B.
Chemistry: molecular biology and microbiology
Micro-organism, tissue cell culture or enzyme using process...
Preparing alpha or beta amino acid or substituted amino acid...
435106, 435233, C12P 1320, C12P 1304
Patent
active
057416818
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for producing L-aspartic acid. In particular, the present invention relates to an industrially advantageous process for producing L-aspartic acid by the aid of an enzymatic action by using maleic acid or maleic anhydride as a raw material.
2. Description of Related Art
L-Aspartic acid is in increasing demand to be used for pharmaceuticals and food additives. Development of new application or use of L-aspartic acid has been also investigated. However, no economically excellent process for industrial production has been established until now. Therefore, it is expected that the demand for L-aspartic acid will greatly increase if mass production is achieved at an inexpensive production cost.
A method for producing L-aspartic acid has been hitherto known, in which L-aspartic acid is obtained in accordance with an enzymatic process by using fumaric acid as a raw material in the presence of ammonia by the aid of the action of aspartase or a microorganism which produces aspartase.
However, in the conventional method, sulfuric acid or hydrochloric acid is used to precipitate L-aspartatic acid from the reaction solution which contains ammonium L-aspartate. Therefore, ammonium salt of inorganic acid, which has a low economic value, is by-produced in a large amount, resulting in increase in production cost for L-aspartic acid.
On the other hand, a method has been proposed, in which ammonium L-aspartate obtained by the enzyme reaction is precipitated by adding maleic acid or maleic anhydride, and a mother liquor containing ammonium maleate after recovery of L-aspartic acid crystals is utilized as a raw material (EP 127, 940). According to this method, maleic anhydride, which is inexpensive and easily obtainable in a large amount, is used as a raw material. Therefore, this method has a potential to be established as an industrially extremely desirable method if desired L-aspartic acid can be obtained in accordance with a stable continuous operation.
However, in the case of the method described in the patent application, upon crystallization starting from ammonium L-aspartate, it is impossible to increase the recovery of L-aspartic acid crystals unless a large amount of maleic acid is added. Therefore, this method is operated on condition that maleic acid is added in a crystallization step in an amount which exceeds an amount of L-aspartic acid to be crystallized. Accordingly, if a mother liquor containing ammonium maleate after crystallization is recycled, i.e., added to a reaction system and used, the concentration of L-aspartic acid in the system gradually increases. Thus it is impossible to successively perform a stable continuous operation. In sum, it is difficult for the method described above to achieve an industrial continuous operation.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a process for producing L-aspartic acid by using maleic acid as a raw material, in which an aqueous solution of produced ammonium L-aspartate is treated to precipitate by adding constant amount of maleic acid, making it possible to perform a well-balanced and stable continuous operation even when a mother liquor containing ammonium maleate after the precipitation is fully recycled to the reaction system.
As a result of diligent investigations by the present inventors taking the aforementioned circumstances into consideration, it has been found out that ammonium maleate produced by crystallization starting from ammonium L-aspartate is monoammonium salt, while ammonium L-aspartate obtained by using the monoammonium salt as a raw material is a mixture of monoammonium salt and diammonium salt. In sum, in order to precipitate L-aspartic acid after the reaction, maleic acid is required in an amount which is not less than an equimolar amount of ammonium L-aspartate, and monoammonium maleate is produced in an amount corresponding thereto. If the resultant amount of monoammonium maleate is used to produce ammonium L-a
REFERENCES:
patent: 391059 (1888-07-01), Takamura et al.
patent: 560653 (1896-12-01), Sherwin et al.
patent: 3391059 (1968-07-01), Takamura et al.
patent: 4560653 (1985-12-01), Sherwin et al.
patent: 5478919 (1995-12-01), Koskan et al.
patent: 5541090 (1996-07-01), Sakano et al.
Fujii Seishi
Kato Naoki
Mine Norioki
Mori Yoshiaki
Watanabe Naoyuki
Lankford , Jr. Leon B.
Mitsubishi Chemical Corporation
Tate Christopher R.
LandOfFree
Method for producing L-aspartic acid does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for producing L-aspartic acid, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for producing L-aspartic acid will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2056861