The synthesis of indole by washed cell suspensions of Escherichia coli

Abstract

Indole is formed from glucose and ammonium salts by washed-cell suspensions of a mutant strain of E. coli (strain 7-4) unable to convert indole into tryptophan. The medium on which the cells are grown influences the amount of indole formed by the harvested cells. Magnesium ions greatly stimulate indole formation when cells are grown on either a synthetic medium or on various complex media. Manganous and ferrous ions stimulate to a lesser extent. Serine appears to be concerned in indole formation, as shown by experiments with cell suspensions of both E. coli 7-4 and a further mutant (E. coli T2-15) which requires tryptophan plus serine or glycine for growth.