Lead-Resistant Bacterial Isolates from Industrial Discharges: Characterization and Bioremediation Insights

Abstract

Heavy metal pollution, particularly lead, poses severe environmental and health risks. Microbial bioremediation offers an ecofriendly and effective strategy to mitigate such contamination. The present work focused on exploring indigenous bacterial isolates capable of withstanding and reducing lead concentrations. Five isolates, designated SLW4, SLW5, LTS7, SLS1, and AN4, were obtained from industrial effluents. Their morphological, physiological, and biochemical characteristics were examined. Optimum growth conditions were identified at 37°C and pH 7. Based on biochemical profiling, SLW4 and LTS7 were identified as Klebsiella sp., SLW5 as Yersinia sp., SLS1 as Vibrio sp., and AN4 as Pseudomonas sp. Minimum inhibitory concentration (MIC) values were determined, and growth kinetics were assessed. Lead bioremediation was quantified using atomic absorption spectrophotometry at 24 and 48 hours. SLS1 exhibited the highest MIC of 650 µg/ml, while AN4 showed the lowest (600 µg/ml). Growth analysis revealed SLW4 with the longest exponential phase and AN4 the shortest. At 24 hours, AN4 achieved the highest lead reduction (74.04%), while SLW4 recorded the lowest (71.93%). After 48 hours, SLW4 demonstrated maximum removal (80.97%) and LTS7 the least (78.85%).The isolates exhibited substantial lead resistance and bioremediation potential, with efficiency increasing over time. These findings highlight their applicability in environmentally sustainable strategies for lead detoxification.