Exopolymeric substances (EPS) produced by bacterial cells play a crucial role in the interaction of the cells with the surrounding environment. Halobacillus trueperi manxer mangrove-16, an adhered bacterial isolate from the mangrove ecosystem was found to produce EPS that was observed by Alcian blue staining and congo red-coomassie blue agar. The EPS of the bacterial isolate exhibited emulsifying properties. Purification of the EPS by dialysis showed an emulsification index of 80% with hexadecane. Qualitative analysis and Fourier's Infrared spectroscopy (FTIR) revealed that the EPS was a glycoprotein in nature. The EPS showed no surface-active properties. Further exploration of the potential of the EPS interaction with metal solutions showed the ability of the bioemulsifier to cause precipitation in the metal solutions and particularly change the color of the Chromium (VI) solution. The scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS) of the cells and EPS particularly indicated the interaction of the EPS with the (Fe0 ) zerovalent iron nanoparticles and its effect on the cells and EPS of the bacteria. It is therefore concluded that the EPS is a crucial component that anchors the bacteria to particulate matter in the mangrove ecosystem and also plays an important role in interaction with metals and hydrocarbons.
Keywords: Fe0 nanoparticles; bioemulsifier; bioremediation; extracellular polymeric substances (EPS); glycoprotein; metal-interaction.
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