Influence of Rifampicin-Resistance Mutations on the Synthesis of Antioxidant, DNA-Protective, and SOS-Inhibitory Metabolites

This work investigates the impact of rifampicin-resistance mutations on the synthesis of secondary metabolites with antioxidant, DNA-protective, and SOS-inhibitory properties in two probiotic strains Bacillus amyloliquefaciens B-1895 and B. subtilis KATMIRA1933. Rifampicin-resistant (RifR) mutants of these strains demonstrated significantly enhanced biological activities compared to their wild-type counterparts. Antioxidant activity increased by 30.39% in B. subtilis KATMIRA1933 and 24.55% in B. amyloliquefaciens B-1895 mutants, while DNA-protective activity rose by 6.67 and 6.27%, respectively. SOS-inhibitory activity also improved, notably by 17.27% in B. subtilis mutants and 3.12% in B. amyloliquefaciens. Genomic analysis revealed the presence of genes responsible for the synthesis of non-ribosomal peptides and polyketides, which are likely contributors to these enhanced activities. These findings suggest that RifR mutants can serve as effective producers of metabolites with antioxidant, DNA-protective, and SOS-inhibitory properties, offering potential applications in agriculture and pharmacology.