ISOLATION, SCREENING AND CHARACTERIZATION OF CADMIUM TOLERANT BACTERIA FROM INDUSTRIAL EFFLUENT

Soil and water contamination with cadmium (Cd) is a severe concern for the developing world due to its non-biodegradability and significant potential to damage the ecosystem and associated services. Industries such as mining, manufacturing, building, etc., rapidly produce a substantial amount of Cd, posing environmental risks. Microremediation generally relies on the metabolic potential of microorganisms such as bacteria, fungi and algae, that have been reported to have a high tolerance for metals. Bacteria are reported to have a significant bioremediation capability in which hazardous pollutants act as a source of energy for cellular development and growth. The present study is therefore aimed at isolation, screening and characterization of cadmium tolerant bacterial strains from the effluent of West coast paper mill, Dandeli. Samples were collected asceptically and subjected to elemental analysis to detect the presence of cadmium. Physiochemical parameters, including Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), CO2 and Total Dissolved Solids (TDS), were assessed. Four cadmium resistant bacterial strains (C1, C2, C3, and C4) were isolated, screened and identified upto the genus level by cultural, microscopic and biochemical characteristics to assess their metal tolerance potential. Among them, C2 strain exhibited significant cadmium tolerance and was subjected to molecular characterization and identified as Klebsiella pneumoniae. Klebsiella pneumoniae was subjected to MIC with various concentrations of cadmium (0.005, 0.010, 0.015, 0.020, 0.025, and 0.030 mg/mL) and was observed that 0.025 mg/mL showed optimum growth which was explored for further analysis. Antibiotic susceptibility test revealed that Klebsiella pneumoniae was sensitive to cefixime and ciprofloxacin, indicating potential safety in environmental applications. The results highlight the promising use of Klebsiella pneumoniae in the bioremediation of cadmium-contaminated aquatic environments.