| Abstrakt: |
A native Bacillus cereus isolate has been employed, for the first time, for simultaneous decolorization, dechlorination of chloroorganics, and Cr remediation from the real tannery effluent. Most of the physicochemical variables in 3:1 diluted effluent were well above the standard prescribed limits, which decreased substantially upon microbial treatment. The extent of bioremediation was better in diluted (3:1) as compared to undiluted effluent supplemented with nutrients and augmented with B. cereus isolate. Maximum growth, effluent decolorization (42.5 %), dechlorination (74.1 %), and Cr remediation (34.2 %) were attained with 4.0 % ( v/ v) inoculum, 0.8 % glucose, and 0.2 % ammonium chloride in 3:1 diluted effluent at natural pH (8.1) within 72 h of incubation. The efficiency of bioremediation in a bioreactor was higher as compared to a flask trial during 72 h of incubation: decolorization (47.9 %) was enhanced by 5.4 %, dechlorination (77.4 %) by 3.3 %, and Cr removal (41.7 %) by 7.5 % at an initial color of 286 Pt-Co units and initial concentration of 62 mg chloride ions and 108 mg l Cr. Immobilized biomass of Pseudomonas putida and B. cereus coculture enhanced the extent of Cr remediation (51.9 %) by 10.2 % compared to the bioreactor trial. Chromate reductase activity and reduced Cr directly correlated and were mainly associated with soluble fraction of B. cereus plus effluent natural microflora. The GC-MS analyses revealed the formation of metabolites such as acetic acid and 2-butenoic acid in bacterially treated effluent. The supplementation of nutrients along with B. cereus augmentation is required for efficient effluent bioremediation. [ABSTRACT FROM AUTHOR] |
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