Bioremediation of lead and manganese from wastewater using different Bacillus spp. with FTIR spectroscopic analysis

Abstract

Both humans and ecosystems are seriously at risk from water contaminated with heavy metals (HMs), such as lead and manganese. This research assesses the biosorption effectiveness of different Bacillus strains, namely: Bacillus licheniformis MSRY R, Bacillus amyloliquefaciens MSRY F, and Bacillus amyloliquefaciens MSRY J, to remove Pb(II) and Mn(II) from aqueous solutions, aiming to identify the best effective strain for wastewater bioremediation in Egypt’s Nile Delta (Kitchener and No. 7 drains) in accordance with discharge standards. Results indicated that Bacillus licheniformis MSRY R eliminated 98%–99% of lead, bringing its concentration to levels close to or below the World Health Organization (WHO) safe drinking-water recommendation of 0.01 mg/L. Additionally, 77% of the manganese was removed, leaving levels that met or remained below the WHO standard of 0.4 mg/L. Notably, FTIR spectroscopic analysis revealed a distinct shift in hydroxyl, amide, carboxylate, and phosphate groups, indicating its involvement in Pb(II) and Mn(II) binding by such Bacillus strains, specifically Bacillus amyloliquefaciens MSRY J, which exhibited the greatest Extracellular Polymeric Substances (EPS)-matrix reorganization at the same time, Bacillus licheniformis MSRY R showed a strong multi-site mechanism. These findings confirm that Bacillus strains provide a viable, environmentally friendly way to remove heavy metals from contaminated water.