The ability of fermentates of two potential probiotic strains, Bacillus amyloliquefaciens B-1895 and Bacillus subtilis KATMIRA1933, to lower the SOS response in bacteria was evaluated using Escherichia coli-based Lux biosensors (pRecA-lux) and the tested bacilli fermentates obtained through solid-state fermentation. The SOS response was stimulated by the addition of ciprofloxacine. Preparations of both Bacillus fermentates demonstrated SOS-inhibitory activity (up to 54.21%). The strain ?ATMIRA1933 was characterized by higher SOS-inhibitory activity. The active components of the fermentates were stable against heating, proteinase, and RNase action.