Characterization of chromium remediating bacterium Bacillus subtilis isolated from electroplating effluent

Chromium, especially chromium (VI), is the main pollutant of the tannery and electroplating industries. Cr (VI) is said to be a hazardous pollutant as it is highly toxic, mutagenic as well a carcinogen. Cr (VI) is mobile as it is soluble in nature. In our present study, indigenous bacteria that are tolerant to high concentrations of Cr (VI) were isolated from chromium contaminated electroplating effluents which were collected and analyzed in different seasons of a year. Among many isolates of season 1, a highly chromium tolerant bacterial strain named PESA, was isolated from effluents of electroplating industries. This study, reports the tolerance ability of the bacteria as well as the identification of the strain PESA by different morphological, biochemical and 16s rRNA gene analysis as Bacillus subtilis and the sequence of which is deposited with NCBI Genbank. The optimal pH value for chromium biosorption was found to be 3.0 and optimum temperature being 30-32 o C. It is found to reduce Cr to >50% upto 93 % in 10 days in a 500 mg/L concentration of media at pH 3.0. Hence the organism has great potential for cleaning of Cr (VI) polluted effluents.