Decolorization of certain reactive dye from aqueous solution using Baker’s Yeast (Saccharomyces cerevisiae) strain

In this study, Baker’s yeast strain (Saccharomyces cerevisiae) was evaluated for its ability to decolorize a synthetic dye aqueous solution and real industry effluent from Giza spinning and weaving company, Giza, Egypt. The removal of color from one of the azo dyes, ramazole blue (Vinyl sulfone), had been carried out by Baker’s yeast using repeated-batch process. Factors such as solution pH, dye concentration and biomass dosage at different interval times were experimentally tested. The effect of pH on dye bioremoval was investigated at a pH range from 1 ± 0.02 to 6 ± 0.02. The optimum pH values were 2 ± 0.02, 1 ± 0.02, 3 ± 0.02, 4 ± 0.02 and 5 ± 0.02 for direct dye removal, respectively. The effect of dye concentrations was studied using different concentrations of synthetic dye containing 100–600 ppm and the effect of biomass weight was also studied at pH 2 ± 0.02 for different interval times. The equilibrium concentration and the adsorption capacity at equilibrium were determined using two different sorption models namely; Langmuir and Freundlich isotherms. These isothermal models were applied to evaluate differences in the biosorption rates and uptakes of textile dye with a high degree of correlation coefficients in case of Freundlich’s isothermal model (R2 = 0.947). At the end of the experiments, the treatment with Baker’s yeast strain could reduce color absorbance and COD value of real textile wastewater by 100% and 61.82%, respectively. Baker’s yeast cells were characterized using SEM and FTIR spectroscopy.