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Abstract : |
NOT AVAILABLE, A consortium of sulphate reducing bacteria (CSRB) isolated from domestic sewage which can tolerate hexavalent chromium concentration upto 2000 ppm. This consortium consists of a range of gram positive (spore and non spore forming) and gram negative bacteria. The reduction of Cr+6 to Cr+3 was observed by change in color from orange yellow to grayish black and setting of amorphous precipitate associated with the bacterial cell surface on the bottom of the culture vessels. The growth of أƒآ¢أ‚€أ‚ثœCRSBأƒآ¢أ‚€أ‚â„¢ was affected by the concentration Cr+6 in the medium. The reduction growth of the أƒآ¢أ‚€أ‚ثœCRSBأƒآ¢أ‚€أ‚â„¢ was increased with the increase in the Cr+6. At 2000 ppm Cr+6 the reduction in growth was 86.78% after 48 hours. The rate of reduction was dependent on the initial concentration of Cr+6 in the medium. 99.68 to 81.89% Cr+6 can be removed from concentration ranging from 50 to 2000 ppm. Above 1000 ppm Cr+6 concentration there was a sharp fall in the reduction percent. The rate of Cr+6 reduction also depends upon the bacterial cell density. Zn+2 supported while Ag+ inhibited the reduction of Cr+6 when added to the culture medium., |
