ISOLATION AND CHARACTERIZATION OF CHROMIUM TOLERANT BACTERIA FROM TANNERY EFFLUENT AT DINDIGUL DISTRICT, TAMILNADU, INDIA

Hexavalent chromium contamination in environment became a serious problem in all over the world. The chromium, a toxic heavy metal, is a major contaminant in tannery wastes and their accumulation into the soil and water is an environmental issue particularly in Tamilnadu. Dindigul is the headquarters of leather tannery industry. Tannery effluent was collected from leather industry located at Dindigul district. Bacteria having tolerance to chromium has been isolated. A total of six species of chromium tolerant bacteria were isolated and their minimum inhibitory concentration of all the six isolates against hexavalent chromium was determined on nutrient agar supplemented with varying concentration of chromium from 100 ppm to 600 ppm. The bacterial strains were characterized by morphological, cultural and biochemical analysis. They were identified as Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus, Micrococcus species, Bacillus cereus and Bacillus licheniformis. The analysis of the results concluded that all the bacteria showed resistance against chromium with Minimum Inhibitory Concentration (MIC) values up to 100 mg/L.