Patent ID: 9120729
Filing Date: 2015-09-01
Classification: C07C

Abstract:
1. A process for purifying L-cysteine from an L-cysteine-containing fermentation broth, comprising: bringing the L-cysteine-containing fermentation broth into contact at a pH of from 6 to 9 with a basic anion exchanger, wherein the anion exchanger is used in an OH flushing the anion exchanger with a first washing solution, contacting the anion exchanger with an acid to remove the bound L-cysteine from the anion exchanger and to form an eluate containing the L-cysteine, contacting the eluate at a pH of ≦4 with an acidic cation exchanger, such that the L-cysteine binds to the cation exchanger, flushing the cation exchanger with a second washing solution, and contacting the cation exchanger with a strong acid to remove the L-cysteine from the cation exchanger and to provide a purified L-cysteine containing solution.