Hexavalent chromium reduction and 16S rDNA identification of bacteria isolated from a Cr (VI) contaminated site

A Gram-positive, hexavalent chromium [chromate: Cr (VI)]-resistant & reducing bacterium, isolated from sukind chromite mines, jajpur, India, was identified as a Brevibacterium casei(Gene Bank Accession Number: EU781952) by gene sequence homology. The strain(designated as APD15) could tolerate chromium up to a maximum concentration of 500 ppm, at optimum temperature and pH 30C and 7 for maximum chromium reduction. Agar supplemented with 100g Cr (VI)/ml as K2Cr2O7 and 0.5% (w/v) dextrose used as a carbon source. The results of the study indicated removal of more than 94% chromium (VI) by Brevibacterium caseidetermined by diphenylcarbazide colorimetric assay.