[Preparation of Bacillus subtilis A-50 mutants by exposure to nitrosoguanidine and ICR-191]

Spontaneous and NG- and ICR-191-induced variability of Bacillus subtilis A-50 with respect to the production of alkaline proteinase (subtilisine) is studied. It is found that ICR-191 induces greater variability as compared with NG under conditions of a low survival. Six mutants synthesizing proteinases showing a changed ability to form enzymes were obtained under the action of the same mutagens.