Biosorption and bioaccumulation of copper(II) and chromium(III) ions from aqueous solutions by microorganisms

The ability of the yeast Pichia stipitis strain to eliminate copper(II) andchromium(III) has been evaluated by using both viable and nonviablebiomass. The effect of copper(II) and chromium(III) ions on the adaptedand non-adapted biomass and also bioaccumulation properties ofPichia stipitis were investigated as a function of initial metalconcentration. The addition of copper(II) and chromium(III) had asignificant negative effect on the growth of yeast. The growth rate ofadapted cells decreased with the increase of copper(II) andchromium(III) concentrations. Although metal ion concentrations usedin the experiments caused an inhibition effect on the growth of P.stipitis, it was capable of removing copper(II) and chromium(III) with amaximum specific uptake capacity of 15.85 mg/g and 9.10 mg/g at100ppm initial copper(II) and chromium(III) concentration. On the otherhand, experimental test results showed that biosorptive capacity of drybiosolids was 20.22 mg/g for cooper(II) and 16.12mg/g for chromium(III).Adsorption data on nonviable cells were found to be well modeled bythe Langmuir and Temkin isotherm, but Freundlich and Jovanovich (J2)isotherms not. Biosorptive capacities were dependent on the pH andtemperature of copper(II) and chromium(III) solutions.