Isolation, Characterization, and Identification of Multiple Heavy Metal and Antibiotic-Resistant Bacteria From Wastewater

Abstract Heavy metals are the most persistent pollutant in wastewater and cause several health and environmental hazards, contaminate soil, and reduced plant growth and productivity. Novel biotechnological approaches through inoculating bacterial strains might be adopted for the remediation of wastewater containing heavy metals. The study was conducted to reduce the toxicity of heavy metals in wastewater through inoculation of bacterial strains. The wastewater samples were collected under aseptic conditions from wastewater canals in Lahore. Bacterial strains were isolated by using nutrient agar media amended with 50 µg mL− 1 of heavy metals e.g. Zn, Cd, Co, and Hg. The multiple heavy metal-resistant bacterial strains were screened for different biochemical and morphological characteristics. Furthermore, selected multiple-heavy metals tolerant strains were evaluated resistance for multiple antibiotics resistance under in vitro conditions. A total of eighty multiple heavy tolerant bacterial strains were isolated from industrial effluents. The biomass of these multiple heavy metals-resistant bacterial strains was recorded in terms of optical density (OD). The strains with heavy maximum OD in 50 µg mL− 1 were selected for antibiotics resistance and revealed five bacterial strains were most resistant against antibiotics. The best-performing strains were identified as Klebsiella sp. strain BH49 and Salmonella sp. BH67 heaving accession numbers of MT074326 and MT074327, respectively, through 16S rRNA partial gene sequencing. Those identified strains might be used as a bioremediation agent for the efficient removal of heavy metals in contaminated wastewater.