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 Aires
Metropolitan Area, Argentina. In order to accomplish the general goal, the microorganism’s tolerance to chromium (VI) will be
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 Aires
Metropolitan Area, Argentina. In order to accomplish the general goal, the microorganism’s tolerance to chromium (VI) will be
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