Isolation and characterization of heavy metal (lead) resistant bacteria for bioremediation of industrial wastewater

Abstract

Lead pollution in industrial wastewater poses an important environmental and health crisis due to its toxicity and persistence. To address this issue, two soil samples were collected from two lead-contaminated industrial zones in Bangladesh, an automobile workshop situated in Mohakhali, Dhaka and an old battery factory area in Comilla. Atomic Absorption Spectroscopy confirmed elevated levels of lead (Pb) (42.6 ppm and 61.5 ppm respectively). Metagenomic analysis of soil samples by bacterial 16s rDNA sequencing revealed diverse microbial populations, dominated by Pseudomonadati and Bacillati phylum, suggesting adaptation to heavy metal stress in natural settings. AAS of the cell free supernatants from isolated bacteria demonstrated remarkable bioremediation efficiency, removing approximately 97% and 95% of lead from 100 ppm lead-supplemented solution. Further analysis by 16S rDNA sequencing of the isolated bacterial strain L1 and L2, revealed morphological adaptations under lead stress and identified both isolates as Priestia spp.