Effects of Chromium bioaccumulation on Saccharomyces cerevisiae cells
Coelho, E.A.P.; Moreira, L.M.C., Menezes, M.A.B.C., Amaral, A.M. and Neves, M.J.
Centro de Desenvolvimento da Tecnologia Nuclear CDTN/CNEN
The pollution of surface and ground water by Cr(VI) leaching from contaminated soils or water waste of industries become a serious problem. The recovery of CR(VI) from dikute aqeous solutions by bioremediation is a emerging fiel of interest. Unlike conventional sorptive resins or organic solvents, bioremediation employs inexpensive materials. Secondary waste from bioremediation process is readily treated and can be easily disposed of by incineration. Brazil has a big production of yeast Sacharomyces cerevisiae as a sub product of sugar cane fermentation. Our goal is investigate the capacity of S. cerevisiae in accumulate chromium when exposed to a liquid solution. The arm of this preliminary work was to observe the behavior of S. cerevisiae laboratory strain (W303-WT) in the presence of chromium. The presence of increased concentrations of K2Cr2O7 (0, 25, 50, 100, 300ppm), proportioned a gradual inhibition of the growth. The growth curve presented an proportional increase on the lag phase with the increase of the chromium concentration. In the presence of chromium was observed an increase of intracellular trehalose concentration. The accumulation of trehalose was function of the exposition time and metal concentration. Yeast cells collected on logarithmic and stationary phase of growth were exposed to different concentrations of Cr (0, 150 and 300ppm) and the incorporation of the metal was determined. The chromium incorporation was dependent on the time of exposition and the initial concentration of the metal. It was observed a K+ (potassium) extrusion when Cr was incorporated. The work demonstrated that S. cerevisiae cells presented capacity to incorporate Cr, the next steps will be done with yeast strains isolated from fermentation process.
Financial support: CNEN/CDTN, CNPq
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