Abstract
1. Some of 5-methyltrypotophan (5MT)-resistant mutants derived from glutamateproducing bacteria such as Brevibacteriwn flavnm, Corynebacterimn acetoglutamicum and Micrococcus glutamicus produced a small amount of L-tryptophan, while tyrosine and phenylalanine auxotrophs of B. flavum did not.
2. 5-MT-resistant mutant derived from the auxotroph for tyrosine and phenylalanine produced 390mg/liter of L-tryptophan at most. A mutant resistant to a higher concentration of 5MT, which was derived from a tyrosine and phenylalanine auxotrophic mutant which was resistant to a low concentration of 5MT, produced 660mg/liter of L-tryptophan. Using this mutant, the effects of the concentrations of components of the culture medium on the L-tryptophan production were examined. The high concentration of L-tyrosine, but not L-phenylalanine, inhibited the L-tryptophan production. Using the improved culture medium, this strain produced 1.9g/liter of L-tryptophan.
