Process for producing citric acid and/or citrates

US6087139A · kind A · utility

Assignee

• Metallgesellschaft AG · DE

Inventors

• Rudolf Boensch · Nackenheim, DE
• Klaus Hohmann · Hofheim, DE
• Juergen Kuhn · Frankfurt am Main, DE
• Vaclav Cerny · Kaznějov, CZ
• Frantisek Hotek · Podbořany, CZ
• Jiri Pendl · Plzeň, CZ

Key dates

• Filing date: Oct 22, 1998
• Grant date: Jul 11, 2000
• Expiry date: Oct 22, 2018

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S435/917
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

Citric acid and/or the salts thereof are produced from a raw material containing carbohydrates. An aqueous solution of the raw material is converted into a first solution containing citric acid by means of fermentation, and from the first solution a second solution containing citric acid is obtained by means of a cell separation. The second solution is subjected to a protein precipitation at temperatures of 2 to 70.degree. C., and protein is separated by filtration. From the filtration, a third solution containing citric acid is obtained, and the same is passed through a first anion exchanger. The solution containing citric acid, which is discharged from the first anion exchanger, is passed through a second anion exchanger, which is selectively charged with citric acid. The second anion exchanger charged with citric acid is eluted with hydroxide solution or water, and there is thus obtained a fourth solution, in which citrate or citric acid is dissolved. Water is at least partly removed from the fourth solution.