[Variability of pigment formation in Mycobacterium rubrum as affected by chemical mutagen action].

The object of this work was to study the effect of N-nitrosomethylurea (NMU), N-nitrosoethylurea (NEU) and N-nitrosodimethylurea (NDMU) taken at different concentrations on the ability of Mycobacterium rubrum to synthesize carotenoids. In contrast to NEU and NDMU, NMU modified the morphology of the organism and intensified the rate of carotene synthesis. The method of stepwise selection with NMU was used to obtain a mutant producing 7050 micrograms/g of carotenoids and capable of synthesizing pigments which were not typical of the wild strain (auroxanthine, cryptoxanthine, lycopine, leprotine and neoxanthine).