The present is study focused on Lab-Scale biotreatment of chromium electroplating effluent using mixed bacterial strains. The electroplating effluent contaminated soil sample was collected and sixteen bacterial colonies were isolated and identified through morphological and biochemical characteristics. All the sixteen bacterial isolates were screened for metal tolerance using nutrient agar medium incorporated with chromium metal ions. Of the sixteen bacterial isolates, only four bacterial strains were found as potential metal tolerant bacterial strains and they were further characterized in the various environmental conditions such as different pH, various temperature and different chromium metal ion concentrations. The results of characterization study revealed that two bacterial strains, i.e., Pseudomonas sp 4 and Staphylococcus sp 2 were found to grow better in medium containing 300ppm of chromium in pH 7 at 37°C on 5th day. Based on molecular sequencing of 16S rRNA, the two bacterial isolates were confirmed asPseudomonas aeruginosa and Staphylococcus caprae. Antagonistic studies between two selected bacterial strains were performed and the results indicated with negative antagonistic activity between the strains. Therefore, these two compatible metal tolerant bacterial strains were further used as bacterial consortium for the treatment of chromium electroplating effluent in the Lab-scale reactor for 5 days. The treated effluent was collected and determined for various physicochemical characteristics through APHA, 1995 methods and also determined the presence of the residual metal through SEM-EDAX, FTIR and AAS analyses. The better performance metal removal was observed in the treatment with of bacterial consortium.
IJPRAS
