The optimization of penicillin biosynthesis in fungi.

Penicillin production by Penicillium chrysogenum is not only commercially important but arguably the most intensively investigated secondary-metabolic pathway in fungi. Isolation of the structural genes encoding the three main penicillin-biosynthetic enzymes has stimulated the use of molecular approaches to optimize yield and permitted genetic analysis of current production strains, which are themselves the products of 50 years of strain and process improvement. Parallel studies on the penicillin-producing genetic model organism Aspergillus nidulans are now addressing questions about the genetic regulation of primary and secondary metabolism, the compartmentalization of biosynthesis and the excretion of the end products.