Cr (VI) Ion Uptake by the Yeast S. Cerevisiae UCM Y-1968 and its Protoplasts
The present study is focused on the investigation of hexavalent chromium uptake by the yeast S. cerevisiae UCM Y–1968 and its protoplasts. For the first time the ability of S. cerevisiae protoplasts to accumulate Cr (VI) ions was shown. Under the influence of various concentrations of Cr (VI) ions, the proportion of the surviving yeast cells and protoplasts decreased as treatment time extended. During 0.5 – 1h of treatment, yeast protoplasts demonstrated a significant level of Cr (IV) ion accumulation, 44 – 47 % of the supplied Cr ions, whereas the initial strain S. cerevisiae UCM Y-1968 accumulated 9 – 10 %. The isotherms for S. cerevisiae UCM Y-1968 were related to L2 types and for yeast protoplasts isotherms were related to L3 types. Cr (VI) sorption/uptake parameters (Qmax, b) for living cells were found for S. cerevisiae UCM Y–1968 (Qmax = 890 μmol/g) and its protoplasts (Qmax = 1335 μmol/g) at the initial Cr (VI) ions concentration of 25 mg/l. The results showed that hexavalent chromium uptake by living yeasts biomass mainly depended on intracellular accumulation. Chromium uptake by protoplasts cells was characterized by simultaneous metabolism-dependent bioaccumulation with prevalence of the intracellular accumulation of Cr (VI) ions.
Edgardo R. Donati, Marisa R. Viera, Eduardo L. Tavani, María A. Giaveno, Teresa L. Lavalle, Patricia A. Chiacchiarini
O. G. Mameeva and V.S. Podgorsky, "Cr (VI) Ion Uptake by the Yeast S. Cerevisiae UCM Y-1968 and its Protoplasts", Advanced Materials Research, Vols. 71-73, pp. 593-596, 2009