BAEZ German David
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Pre-treated brewer's yeast in the detoxification of effluents polluted with copper
BUSTI, PABLO; BÁEZ, GERMÁN; MORO, ANDREA; BALLERINI, GRISELDA; DELORENZI, NÉSTOR
Workshop; 1st Argentinien Workshop on Environmental Science; 2009
Faculty of Biochemistry and Pharmaceutical Science National University at Rosario
Industrial heavy metals waste contaminates the water remaining as an unsolved serious problem. Nowadays, the available chemical processes are too expensive when they are used to purify high volume of polluted water with low levels of contaminants. A cheaper way of treatment consists of the utilization of microorganisms as heavy metals adsorbents. The presence of charged groups in the cellular surface enables their behaviour as ionic exchanger. Using the dead biomass from industrial fermentations (brewer industry, bread manufacture, etc.) enables making the whole process cheaper. Several physical-chemical treatments can be used in order to modify the bio-adsorbent properties, through the exposure of a higher number of sites where the contaminant can be linked, resulting in a greater adsorption efficiency. The main aim of this work was studying the detoxification of copper(II) by adsorption with a dead biomass (Saccharomyces cerevisiae). The alive biomass was treated in tour different ways: a) thermic treatment (by heating in autoclave), b) thermic-chemical treatment (NaOH 1 M in autoclave), c) chemical treatment (with absolute ethanol) y d) oxidation (with KMnO4). The treated dead biomass was washed and dried at 60 °C and taken into dust by grinding in a mortar. The adsorption isoterms (fixed copper (g) / dry biomass(g) vs. equilibrium copper concentration) were plotted at pH 4,0 y 5,0 and both at 20 °C. The equilibrium copper concentration was determined by cuprizona colorimetric method. The obtained isoterms were adjusted with the Langmuir model of adsorption, and making a comparison among them the outcome order of efficiency was: oxidation treatment >> thermic-chemical treatment > thermic treatment > chemical treatment with ethanol. Thus, the oxidation treatment would be the chosen one among the assayed treatments to achieve an acceptable degree of purification for these type of effluents.