Mutants of Bacillus megaterium with altered synthesis of an exocellular neutral proteinase.

Germinated spores of Bacillus megaterium were mutagenized with ethyl methanesulphonate and spread on test agar with caseinate. Colonies with altered proteolytic zones or morphology were isolated and tested in liquid media. The mutants can be divided into four groups: A) those producing more proteinase in both growth and sporulation media, B) those producing the same amount of the enzyme in growth medium but higher amount in sporulation medium, C) those producing less proteinase in the growth medium and more in the sporulation one, D) those producing less or no enzyme. Clones of the first three groups were phenotypically asporogenic. All mutants producing more enzyme during growth retained their sensitivity to repression by amino acids. Isolation of mutants of types B) and C) supports the idea of differences in the control of proteinase synthesis during growth and during sporulation.