Industrial effluent and common effluent treatment plant (CETP)-associated samples from Navi Mumbai, India, were screened for indigenous lead-tolerant bacteria. Among 32 isolates, EP-L-21 showed the highest Pb tolerance, with growth at the highest tested concentration (>2,000 mg/L) Pb, broad pH tolerance (pH 4–10), and robust growth across 20-37 \(^\circ \) C, with consistent optical density at 600 nm (OD \(_{600}\) ) values indicating broad temperature tolerance under Pb stress. VITEK® 2 identification and whole-genome sequencing (WGS) assigned EP-L-21 to Klebsiella pneumoniae (K. pneumoniae) sequence type 86 (ST86). The draft genome (5.38 Mb; 57.3 mol% GC; 46 contigs) encoded metal-resistance and stress-response determinants, including resistance-nodulation-division (RND)-family efflux systems, P-type ATPases, oxidative stress-associated genes. In addition, enterobactin- and aerobactin-associated siderophore biosynthetic clusters were identified, which may contribute indirectly to metal-stress adaptation under iron-limited and metal-stressed conditions; no canonical czcCBA operon was detected. In Luria–Bertani (LB) broth containing a measured initial supernatant-associated Pb concentration of 88.40 ± 0.43 mg/L, residual supernatant-associated Pb decreased to 0.58 ± 0.43 mg/L after 72 h, corresponding to 99.34% removal, whereas abiotic controls showed negligible Pb loss. Pb reduction over time was statistically significant ( \(p < 0.001\) ). Mass-balance analysis indicated that >99% of removed Pb was associated with non-supernatant fractions, although surface-bound, intracellular, and precipitated pools were not independently resolved. EP-L-21 also exhibited tolerance to Ni, with intermediate resistance to Cr, Cd, and sensitivity to Hg at lower concentrations. Genome analysis predicted the presence of antimicrobial resistance (AMR) and virulence-associated determinants, therefore, the strain should be considered an environmental opportunist and is suitable only for contained bioreactor-based applications, with environmental release not recommended. These findings link high-level Pb tolerance with a predicted multimetal resistome and support further mechanistic validation in contained bioprocess systems.
