THE SEARCH FOR BACTERIAL PRODUCERS OF 1,4-DIAMINOBUTANE
60 Escherichia coli natural isolates were examined for the ability to produce 1,4-diaminobutane (putrescine) under various cultivation conditions. The maximum concentration of intracellular 1,4-diaminobutane was 192 nmol/mg dry weight, that was 5-fold higher than that of the laboratory K12 strain. The highest concentration of putrescine released into the medium was 207 μM, which was 16 times higher than those of K12 culture. Natural isolates also produced spermidine, a substrate for the biosynthesis of 1,4-diaminobutane. The highest concentration of spermidine in the cell was 40 nmol/mg dry weight. There was no spermidine in the medium.