Observation of Adsorbed Cu2+ by a Winthrop Biofilm Using SEM-EDS

Biofilms are collections of bacteria that congregate to better their chance for survival. To create the biofilm, bacteria secrete a mixture of polysaccharides, proteins, and nucleic acids, which is known as the extracellular polymeric substance (EPS). This EPS attaches the cells to a surface, traps nutrients, and allows for horizontal gene transfer. It has been documented that some biofilms can take up metal ions from their environment, and have been used in the bioremediation of polluted areas. A previous experiment showed that a biofilm collected from the Winthrop Successional Plots was able to adsorb copper from its environment. In this experiment, the same biofilm was exposed to copper in order to determine the location of copper storage. The specimens were sectioned and fractured using the Tanaka protocol, in order to view the inside of the biofilm, and SEM-EDS was used both to determine if there was a difference in the amount of copper present between the experimental and control groups, and if there was a difference in the amount of copper present between the EPS and the cells