Jornal de Biorremediação e Biodegradação

Abstrato

Bacterium Isolated from Coffee Waste Pulp Biosorps Lead: Investigation of Biosurfactant Mechanism to Bioremediate Lead Pollution

Shiny Martis B, Aparna K Mohan, SanjanaChiplunkar, SandhyaKamath, LouellaConceptaGoveas, C VamanRao

Klebsiella pneumoniae Kpn555, isolated from coffee waste pulp showed high level of tolerance to lead with a minimum inhibitory concentration of 900 mg/L. On its growth in nutrient broth supplemented with lead, brown clumps were visualised at the bottom of the flask. On scanning and transmission electron microscopic studies the brown clumps were corroborated to be bacterial cells with lead biosorbed on the cell surface and accumulated inside the cytoplasm. Isolation of plasmid from K. pneumoniae Kpn555 revealed the presence of a plasmid of size 30-40 kb. This capability of the bacteria was proven to be plasmid mediated as the Escherichia coli DH5α cells transformed with the plasmid of K. pneumoniae Kpn555 also could tolerate 900 mg/L of lead and form brown clumps. The heavy metal bioremediation activity of the produced biosurfactant was also investigated. The biosurfactant was subjected to biochemical characterisation as well as FTIR analysis to establish the chemical nature of the produced molecule. The highest metal removal rate using the biosurfactant was found to be 50% at 400 ppm of Pb. This study shows that this bacterium serves as an effective agent for the removal of lead from contaminated sites.