Comparison of thallium species uptake by raw and treated Saccharomyces cerevisiae

LETICIA B. ESCUDERO; NAHUEL BUSTOS; GUSTAVO LASCALEA

Mar del Plata

Encuentro; VIII ENCUENTRO LATINOAMERICANO Y DEL CARIBE DE BIOTECNOLOGÍA; 2013

REDBIO

Metals pollution is an increasing problem mainly caused by anthropogenic activities. To solve contamination, the use of microorganisms has been used for removing metals from solutions. In this work, a comparison between the use of raw and treated Saccharomyces cerevisiae cells for Thallium (Tl) species uptake was developed. Sorption studies were performed in flasks containing solutions with concentrations from 1 mg/L Tl of each species. Different processes applied to the biomass, including treatment with temperature, organic solvents and surfactants were developed to improve metal uptake. The effect of pH, contact time, ionic strength, and yeast mass was also studied. Thallium was determined by electrothermal atomic absorption spectrometry (ETAAS). Metal accumulation in the cells was dependent of pH. Kinetic studies showed a maximum uptake of Tl species after 24 h for non treated cells (44 and 63% for Tl(I) and Tl(III), respectively). An improvement of these metal uptakes was obtained with a stirring contact (73 and 75%). Regarding treated yeasts, neither thermal nor caustic treatments were useful to improve Tl species uptake. However, solvent treatment showed a significant improvement. This work opens the possibility of developing bioremediation processes based on the high performance of yeast for Tl species uptake.