Heavy Metal Tolerance and Copper Uptake in Yeast Isolated from Patagonia/ Argentina

In recent years the use of microbial methods for decontamination or recovery of heavy metals from environment has increased. Microorganisms such as yeasts are potential bioremediators, removing metals via active or passive uptake. Pink-coloured and pigment-less yeast strains isolated from Agrio River, Patagonia Argentina, were tested for copper, nickel, cadmium and zinc tolerance. An agar-plate qualitative screening method using YNB-glucose agar at different metal concentrations was employed. The tolerance to the metals varied depending on the strain tested. A pigmented yeast strain (Agrio 16) was selected by its tolerance. The ability of this strain to copper uptake was investigated. The kinetics of bioaccumulation/biosorption with increasing copper concentrations up to 622.8 mg l-1 were carried out using viable and nonviable biomass. The values of constants k and n obtained for the Freundlich model are 0.0418 and 0.7430, respectively. The maximun sorption uptake capacity (q) for viable biomass was 81.6 mg of copper/g of biomass.