de la Nación Argentina). The monthly average Cr(VI) maximum value informed in literature is 0.077 mg/L for industrial wastewater discharges [6]. European Union recommends total chromium limits of 0.05 and 0.1 mg/L for potable and industrial wastewater respectively [http://europa.eu/]. That is why other alternative technologies are necessary to remove Cr(VI) to fulfil the national legislation requirements. Microbial treatments, based on biotransformation of Cr(VI) to Cr(III) which is easily immobilized as Cr(OH)3, are still efficient with low Cr(VI) amounts. These methods offer an economical as well ecofriendly option for chromate detoxification and bioremediation [7]. A number of chromium resistant microorganisms had been reported to detoxify hexavalent chromium [8], where the method of detoxification could be periplasmic biosorption, intracellular bioaccumulation and biotransformation directly through enzymatic reaction or indirectly with metabolites [5]. The objective of the present study is the application of either axenic or mixed cultures for Cr(VI) biotransformation followed by chemical flocculation of Cr(OH)3 as a combined treatment for industrial wastes, with Cr(VI) concentrations below 2 mM. The
microorganisms to be tested were isolated from polluted soil, surface water and sediments of industrial areas of Buenos AiresMetropolitan Area, Argentina. In order to accomplish the general goal, the microorganism’s tolerance to chromium (VI) will be