Lysine stimulation of cephalosporin C synthesis in Cephalosporium acremonium

Summary

Lysine added to a defined medium at a concentration of 1 mg/ml enhances the capacity of Cephalosporium acremonium to produce cephalosporin C. The lysine effect was accompanied by a delayed differentiation to arthrospores followed by more extensive mycelial fragmentation. Higher lysine concentrations reduced the synthesis of cephalosporin C. The effect of lysine on cephalosporin C synthesis was not strain related and was not elicited by the other amino acids tested. Both lysine stimulation and inhibition were evidenct using resting cells. The lysine inhibition of cephalosporin C synthesis with resting cells was relieved by supplementing the medium with 1 to 2 mg/ml α-aminoadipic acid. This reversal supports the hypothesis that lysine restricts the availability of α-aminoadipic acid for β-lactam biosynthesis.