Industrial Biotransformations

Tryptophan synthase
Escherichia coli
● l-Tryptophan is produced in such high concentrations that it crystallizes instantly and it is isolated
together with the cells at the end of the fed batch.
● The crude l-tryptophan is solubilized in hot water and the cells are separated after addition of
charcoal.
3) Flow scheme
Fig. 4.2.1.20 – 2
4) Process parameters
yield: > 95 % (based on indole)
reactor type: fed batch
capacity: 30 t · a –1
residence time: 6 h / batch
space-time-yield: 75 g · L –1 ·d –1
down stream processing: multiple fractional crystallizations from aqueous solution
enzyme activity: 250 U · L –1
enzyme consumption: 4,500 U · kg –1
enzyme supplier: AMINO GmbH, Germany
start-up date: 1988/89
production site: Amino GmbH, Germany
company: Amino GmbH, Germany
5) Product application
● l-Tryptophan is used in parenteral nutrition (infusion solution) and as a pharmaceutical active
ingredient in sedatives, neurolepticas, antidepressants and food additives.
● Intermediate for production of other pharmaceutical compounds.
6) Literature
EC 4.2.1.20
● Bang, W.-G., Lang, S., Sahm, H., Wagner, F. (1983) Production of l-tryptophan by Escherichia
coli cells, Biotech. Bioeng. 25, 999–1011
● Plischke, H., Steinmetzer, W. (1988) Verfahren zur Herstellung von l-Tryptophan und
d,l-Serin, AMINO GmbH, DE 3630878 C1
● Wagner, F., Klein, J., Bang, W.-G., Lang, S., Sahm, H. (1980) Verfahren zur mikrobiellen Herstellung
von l-Tryptophan, DE 2841642 C2
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