Biodegradation and decolorization of azo dyes by adherent Staphylococcus lentus strain

A Staphylococcus lentus strain, isolated from Red sea water, was tested for decolorization capacity of Congo red, Evans blue, and Eriochrome Black T azo dyes. Biodegradation (100 mgl−1) of these dyes was studied within 24 h in Mineral Salt Medium solution containing 0.10 % (w/v) yeast extract and 7 mM of glucose at a pH of 7.2 and a temperature of 37 °C. Using a 2.2 × 106 CFU/mL inoculum size, S. lentus was able to decolorize these azo dyes with different degree. The staphylococcal biomass achieves approximately 100 % decolorization of Congo red and Eriochrome Black T by the end of treatment. FTIR and UV–Vis analyses confirm biodegradation potential of the tested strain. Moreover, the phytotoxicity of the dye solutions resulting from this treatment shows lower toxic nature compared to untreated solution of the respective dyes.