Isolation and Screening of the Heavy Metals, Antibiotics Resistant and Acidophilic Profile of Bacterial strains from Lead Acid Batteries Repairing and Recycling Units

Background: Heavy metal contamination from unregulated waste disposal poses serious risks to ecosystems, soil, water, and human health. Lead acid battery recycling sites are major sources of such pollution. This study aimed to isolate and characterize bacterial strains with potential for bioremediation from lead acid battery workshops in Shoba Bazaar, Peshawar.Methods: Water samples were collected from contaminated sites and cultured in both nutrient agar and LB media. After incubation, 30 bacterial isolates were screened for tolerance to cadmium, lead, zinc, and chromium (50–300 mM), as well as resistance to commonly used antibiotics (ampicillin, amoxicillin, azithromycin, cefixime, and kanamycin). The most tolerant strains, designated LRB1, LRB2, and LRB3, were further analyzed for acid and temperature resistance. Morphological and molecular characterization included Gram staining, microscopic analysis, plasmid isolation and genomic DNA extraction.Results: Isolates LRB1, LRB2, and LRB3 demonstrated high lead tolerance of 270 mM, 300 mM, and 270 mM, respectively. All three strains exhibited resistance to multiple antibiotics like ampicillin (10μg), amoxicillin (30μg), azithromycin (15μg), cefixime (5μg) and kanamycin (30μg), and LRB3 showed growth across a broad pH range (2–8). Plasmid DNA was successfully isolated, indicating potential plasmid-mediated resistance. Gram staining revealed that the isolates were Gram-positive bacilli and cocci. Furthermore, genomic DNA extraction and 16S rDNA PCR with universal primers were used for detection and identification of the bacterial isolates.Conclusion: The isolated bacterial strains demonstrated remarkable tolerance to heavy metals, acids, and antibiotics, suggesting their potential role in the bioremediation of contaminated environments. Further molecular studies are required to elucidate the mechanisms underlying their resistance and to evaluate their suitability for biotechnological applications.