Investigation of Saccharomyces Cerevisiae yeast effect on the removal of toxic metals from waste water

In this study it is aimed to remove Lead (Pb) ions by biosorption process using dead fungal biomass Saccharomyces cerevisiae. The influence of pH, biosorbents dose, temperature, concentration of metal ions , contact time on biosorption capacity of Pb(II) ions was studied. The optimum conditions of Pb(II) ions biosorption obtained from the study were: pH 5.0, temperature 25 °C, initial Pb(II) concentration 75 ppm and biomass concentration 5 g/L. At these conditions, maximum Pb(II) uptake was 11.87 mg/g. It was observed that, 0.1 M EDTA solution was an effective chelating agent for desorption of Pb(II) ions from Pb(II) loaded biomass. Both ethanol and sodium hydroxide treatment enhanced the Pb(II) biosorption capacity. The cells at lag phase of growth curve of S. cerevisiae have a higher biosorptive capacity for Pb(II) ions than that of stationary phase.Biosorption of Pb(II) ions by S. cerevisiae explained well with Langmuir model and biosorption kinetics of Pb(II) ions follows pseudo-first order rate model.The heat of biosorption of Pb(II) ions was calculated as -1.70 kcal.mol-1. The activation energy of Pb(II) ions was determined as -2,30 kcalmol-1. According to these values, it was determined that biosorption was an exothermic process and occured by physical adsorption.