Biosorption of heavy metals using bacterial isolates from e-waste soil

The discharge of untreated wastes containing heavy metals into the environment is a challenge to living cells, and in the search for treatment method, biosorption has been an economical and easy technique for heavy metals removal. This study was carried out to determine the biosorption capacity of bacterial isolates from electronic wastes soil. The isolates from e-waste soil were screened and selected for heavy metals such as Chromium (Cr), Lead (Pb), Copper (Cu), and Cobalt (Co), using agar plate method incorporated with 10 ppm of analogous solution of the test heavy metals with each isolate spotted on the agar surface and incubated for 4 days, revealed that Bacillus cereus S13 had the highest biosorption efficiency (highest zone of clearance) of 98% for Pb and Cu, while the least adsorbed metals were Pb (93.5%), Co (93.7%), and Cr (93.9%) by B. cereus S25. The biosorption potential of the selected bacteria was measured with atomic absorption spectrophotometer (AAS). The spectrophotometric analysis of heavy metals biosorption by isolates showed that B. cereus S13 efficiently removed 97.4% Cr and 95.9% Pb, while B. cereus S36 adsorbed 95.5% Pb and Cr at 20 ppm. B. cereus S27 biosorption capacity increased with increase in concentration of heavy metals used except for Pb (96.9%) where larger percentages were removed from the solution at lower concentration. Conclusively this study affirmed that B. cereus strains from electronic waste remediated heavy metals in aqueous solution and therefore, could be promising adsorbent of heavy metals particularly chromium, lead, and cobalt.