The biosynthesis of penicillin. 4. The synthesis of benzylpenicillin by washed mycelium of Penicillium chrysogenum

Abstract

Washed mycelium of P. chrysogenum (strains WIS 48-701, and WIS 51-20), resuspended in water, required only O2 and phenylacetate for the continued synthesis of penicillin. The pH of the medium had no significant effect between the limits 5.8 and 7.8. The synthetic ability of the mycelium degenerated after 1-2 days at 2[degree]. Substances known to give rise to penicillin in complete fermentations were also utilized for the synthesis of penicillin by washed mycelium. The incorporation of potassium (1-C14) phenylacetate, (S35) sulphate, L-(S35) cystine and L-(Cl4) valine into penicillin by incubation with washed mycelium for 3 hours was 3.7, 0.8, 2.5 and 0.27% respectively. Penicillin synthesis was more sensitive than respiration to poisoning by cyanide. The results obtained differ quantitatively from those of Rolinson (Jour. Gen. Microbiol. (11): 412. 1954), and the reasons for this are discussed. The use of washed mycelium provides a convenient method for the investigation of penicillin biosynthesis, since many variables may be tested in a short time in a medium free from interfering substances.[long dash]Auth. summ.