STUDIES ON MUTANTS OF BACILLUS SUBTILIS REQUIRING D-GLUTAMIC ACID

I. ISOLATION OF MUTANTS

Abstract

To produce D-glutamic acid-requiring mutants, spores of Bacillus subtilis K were exposed to X-rays. The mutants were selected by the replica plating method following the penicillin screening. Using a medium enriched with D-glutamate in stead of the so-called complete medium, five D-glutamate dependent mutants were isolated. They were classified into three groups in terms of the growth response pattern (Table 2). Mutant 3d grows in minimal medium when it is supplemented with either D-glutamic acid, D-aspartic acid, or D-alanine. Meanwhile the mutant does not grow in the media when L-aspartic acid or L-glutamic acid coexists.