Synthesis of D-cysteine from a racemate of 3-chloroalanine by phenylhydrazine-treated cells of Pseudomonas putida CR 1-1

3-Chloro-d-alanine chloride-lyase, which occurs in the cells of Pseudomonas putida CR 1-1, catalyzes the β-replacement reaction of 3-chloro-d-alanine in the presence of a high concentration of sodium hydrosulfide to form d-cysteine. Using the β-replacement reaction, the synthesis of d- cysteine from a racemate of 3-chloroalanine by resting cells was investigated. In order to depress the synthesis of l-cysteine from 3-chloro-l-alanine and the enzymatic degradation of 3-chloro-l- alanine, treatment of the cells with 5mM phenylhydrazine was utilized. Under the optimal conditions, 94% of the added 3-chloro-d-alanine could be converted to d-cysteine and 81% of the added 3-chloro-l-alanine was recovered.