Sorptive properties of the biofilm matrix for heavy metals sequestering

• Main Author: Wang, Beatrice Qi An
• Other Authors: Cao Bin
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Environmental engineering::Hazardous substances
• Online Access: http://hdl.handle.net/10356/52982
• Institution: Nanyang Technological University

The effect proteinaceous amyloid component has on the sorptive ability of Pseudomonas aeruginosa was investigated using inductively coupled plasma (ICP) to provide insight on the deviation in the adsorption of metal ions in its absence. To explore the effect of amyloids on the cell, experiment was carried out on a mutant strain with the deletion of Fap, a major subunit in the gene coding of amyloid. The cell surface physiochemical properties of wild type PAO1 and mutant strain Δfap were studied by conducting tests on their hydrophobicity and zeta-potential. The extracellular polymeric substance were then isolated using the cations resin exchange approach and analysis was perform on the quality of EPS based on its protein and polysaccharide contents. After these preliminary tests on the cell samples, PAO1 and Δfap were inoculated with various known concentrations of copper and zinc and were left to incubate. The adsorption ability of each cell was then identified by comparing the final concentration of the metal ions in each sample with the initial known exposure level of heavy metals. The ICP technology was used to detect the low level of final concentration of copper and zinc after adsorption. It was concluded that the presence of amyloid does in fact affect the adsorption of metal ions by Pseudomonas aeruginosa and it acts as a sink to the cell at low exposure to heavy metals. Concurrently, environmental bacterial biofilm was analyzed using water sample collected from a river in Singapore. The analysis was based on confocal laser scanning microscopy and epifluorescence microscopy.