Isolation and Identification of Lead (Pb) Solubilizing Bacteria from Automobile Waste and Its Potential for Recovery of Lead from End of Life Waste Batteries

Abstract

End of life waste Lead (Pb) acid batteries are one of the largest sources of secondary lead production globally. Recycling lead by melting down used batteries is a commercial trade all over the world; but, regrettably, reprocessing lead from end of life batteries is reported for anthropogenic lead exposures causing harsh human health consequence and environmental pollution. The current research intends to isolate and identify Lead (Pb) solubilizing bacteria from automobile waste deposits from Agartala city in Tripura state of India. Scanning Electron Microscope equipped with energy-dispersive X-ray characterization of the grounded lead sample was carried out, and the micrographs demonstrated scattered structures across the matrix. The X-ray diffraction (XRD) spectrum indicates the presence of Lead Oxide (PbO), Lead dioxide (PbO2), and Lead sulfate (PbSO4) in the collected samples. A single bacterium viewing observable growth on Pb supplemented plates was isolated and its Pb recovering capability was estimated through ICP AES analysis. Molecular characterization of the bacterium was investigated using 16S rRNA sequencing along with isolated culture was taxonomically grouped as Cupriavidus sp. The genomic DNA sequences were submitted in NCBI GenBank with the accession number MG171197. In the present case of inspection, the ability of the bacterial strain to recover Pb from end life battery waste was carried out in laboratory scale on a shake flask for 20 days. The experiment conducted under optimum bioleaching parameters with initial pH 6, 5% w/v of microbial culture, 2% pulp density and 2 g/100 mL dextrose concentration at 30 °C temperature with a speed of 200 RPM resulted in 67% Pb recovery from the battery sample. This investigation emphasizes the significance of Pb recycling ability of native bacterial isolate for efficient Pb bio-recovery from end of life waste batteries.