Rec effect of certain textile dyes in Bacillus subtilis

A large number of compounds are toxic, genotoxic, mutagenic, teratogenic and/or carcinogenic. The genotoxicity of four textile dyes commonly used in India namely Sulphur Red Brown 360 (SRB), Jade Green 2G (JG), Reactofix Turquoise Blue 5GFL (RTB) and Direct Scarlet 4BS (DS) was determined by Bacillus subtilis spore Rec assay, both in the presence and absence of metabolizing activation mixture (S9 mix). Each dye was toxic at higher dose levels. A dose-dependent increase in the depth of growth inhibition zones was observed for all dyes. Zones of inhibition were usually clearer at higher doses of the dyes and with Rec− bacteria, but were translucent with Rec+ bacteria. SRB and DS were toxic to Rec+ and Rec− bacteria. JG was less genotoxic in the absence of S9 mix, however, its genotoxic potential increased in the presence of S9 mix. Reactofix T blue was more genotoxic in the absence of S9 mixture.