Stress responses in pigmented Bacillus Pumilus SF14

Abstract

Microbial producers of carotenoids belongs to a various species of unicellular algae, filamentous fungi and several bacteria. A recent report has shown that up to 15% of aerobic spore-formers identified from soil samples are pigmented and in many cases the pigments are carotenoids. Pigmented spore-forming Bacillus was obtained from culture maintained in the microbial culture collection of Department of Structural Functional Biol. University of Naples Federico II and partially characterized their pigments. A classical mutagenesis approach has been used to obtain mutant strains producing altered pigments or no pigments. Our results suggest that pigmentation in spore’s represent an additional, and may be alternative protection strategy against oxidative stress. A mutants (SF214-M1, SF214-M2, SF214-M3 and SF214-M4) of Bacillus pumilus strain SF214 producing a carotenoids water soluble-pigment were obtained after treatment with the mutagenic agent N-Methyl-N-nitroso-N'-nitroguanidine (NTG). Several microbiological and biochemical properties of these 4 strains were analyzed and the results were differences between wild type and other four mutants in producing pigments, color changing, sporulation, cannot produce spores after mutation and sporulation efficiency was constant with color development.