Introduction:

The current study aimed to identify and characterize promissory microorganisms in bioremediation of waters contaminated with hexavalent chromium.

Method:

The isolation and purification of three bacterial isolates from a electroplating was achieved, of the three microorganisms isolated was chosen the bacterial isolated G3 for showed a good potential in bioremediation of hexavalent chromium. The morphological and biochemical characterization and phylogenetic inferences based in the gene of the rRNA 16S of isolated selected was performed; current study evaluated the potential for the reduction of hexavalent chromium associated to biological activity and enzyme activity of chromate reductases using cell-free extract. Additionally, bioassays of reduction of hexavalent chromium with the three microorganisms isolated was performed.

Results:

Biochemical tests and analysis of the 16S rRNA gene suggest that the bacterial isolated G3 belongs to Bacillus cereus sensu lato group. The 100% of reduction of hexavalent chromium in bioassays for 10 mg/L was reached at 10 hour in LB medium and 34 hours in industrial wastewater. The cell-free extract showed chromium reduction activity with optimum values at the temperature of 28°C and pH 6.5. The assay realized with the three microorganisms together on the reduction of chromium is showed five times less efficient than the assays realized only with the strain G3.

Discussion or Conclusion:

The results suggest that Bacillus sp. G3 is a promissory microorganism with good potential for bioremediation processes of water contaminated with hexavalent chromium, in particular concerning detoxification of industrial wastewater.

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