Biotransformation of tryptophan by Phaseolus vulgaris suspension culture.

The carboline alkaloids, harman and norharman, detected in the culture filtrate of Phaseolus vulgaris suspension culture are the two major products of the biotransformation of tryptophan by this culture. The peak concentration of harman and norharman in the medium was reached between the second and fourth day of fermentation, depending on the size of the inoculum. A supplement of 0.1 mg of tryptophan per ml of 67V medium (with a low basal concentration of 15 to 20 mug of tryptophan per ml medium) increased the peak concentration of harman by an average of 2.1 times and of norharman by an average of 4.7 times in medium.