Relation of Dual Phenomenon in Penicillium notatum to Penicillin Production

Abstract

P. notatum was found by a single spore analysis of a stock culture to contain 2 components, a conidial or C type and an abnormal mycelial or M type. The latter arises as a mutant in ageing C colonies, and is morphologically and physiologically distinct. It produces very little penicillin. Maximum production is maintained by choosing the highest yielding clone of P. notatum and keeping it monotypically pure and free from recurring mutants.