Isolation and Some Characteristics of Haemin Dependent Mutants of Bacillus subtilis

Abstract

Hemin dependent mutants were isolated from B. subtilis after ultraviolet irradiation and selection by streptomycin, exposure of the organisms to copper ions and treatment with N-methyl-N[image]-nitro-N-nitrosoguanidine. The isolates were grown in a synthetic medium containing hemin when substances able to neutralize inhibitory factors and to stabilize the medium were included. Two of the mutants were capable of growth in media supplemented only with [delta] -amino-levulinic acid, the first intermediate of porphyrin synthesis. Transformation of the mutants to hemin independence was accomplished using DNA.