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B6db references: 90234222

type Journal Article
authors Ishiwata, K.; Fukuhara, N.; Shimada, M.; Makiguchi, N.; Soda, K.
title Enzymatic production of L-tryptophan from DL-serine and indole by a coupled reaction of tryptophan synthase and amino acid racemase
journal Biotechnol Appl Biochem
Activity 5.1.1.10
ui 90234222
year (1990)
volume 12
number 2
pages 141-9.
 
keywords Amino Acid Isomerases/*metabolism
abstract Enzymatic production of L-tryptophan from DL-serine and indole by a coupled reaction of tryptophan synthase and amino acid racemase was studied. The tryptophan synthase (EC 4.2.1.20) of Escherichia coli catalyzed beta-substitution reaction of L-serine into L-tryptophan and the amino acid racemase (EC 5.1.1.10) of Pseudomonas putida catalyzed the racemization of D-serine simultaneously in one reactor. Under optimal conditions established for L-tryptophan production, a large- scale production of L-tryptophan was carried out in a 200-liter reactor using intact cells of E. coli and P. putida. After 24 h of incubation with intermittent indole feeding, 110 g liter-1 of L-tryptophan was formed in molar yields of 91 and 100% for added DL-serine and indole, respectively. Continuous production of L-tryptophan was also carried out using immobilized cells of E. coli and P. putida. The maximum concentration of L-tryptophan formed was 5.2 g liter-1 (99% molar yield for indole), and the concentration decreased to 4.2 g liter-1 after continuous operation for 20 days.
last changed 2002/11/12 16:17

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