Increasing industrialization and urbanization results in the waste discharge to the environment, which in turn creates
more and more pollution. The discharge of toxic effluents from various industries adversely affects the water resources,
aquatic organisms and ecosystem integrity. These dyes are carcinogenic for both animal and human beings. Biological
treatment either by bacteria, fungi or consortia of both have been reported to reduce the toxicity of dyes to the
permissible limit of discharge to the environment. In the present study, the removal of color of methyl orange fromaqueous solution had been carried out by Baker's Yeast (Saccharomyces cerevisiae). Different factors such as solution
pH, dye concentration and biomass dosage at different interval times were experimentally tested using repeated-batch
process. The effect of pH on dye bio-removal was investigated at a pH range from 3 to 11. The optimum pH values
were3, 5, 7, 9 and 11 for direct dye removal. The effect of dye concentration was studied using different concentrations
of synthetic dye solutions containing 100 – 600 ppm, while the effect of biomass weight was studied in the range1-5 g/L
at pH 5 ± 0.1. The effect of salinity on dye bio-removal process was investigated at the optimum pH, at concentrations (2,
3 and 4 g/l) of NaCl. The effect of glucose as a nutrient was evaluated for different concentrations of glucose (20, 40 and
60 ml/L).