Metal-binding compounds microorganism-produced

As previously indicated, many microorganisms produce EPS or slime, and several researchers have investigated the role of EPS in corrosion [86-88]. EPS consist of polysaccharides and proteins, plus significant amounts of nucleic acids, (phospho) lipids and humic substances [89-91]. The final composition of the EPS matrix results from a combination of the following active secretion, shedding of cell surface material, cell lysis, and/or adsorption of substances from the environment. EPS are usually acidic and contain functional groups, such as carboxylic and amino acids that, as mentioned earlier, readily bind metal ions. EPS can bind metal ions from the substratum or from a liquid medium and control interfacial chemistry at a metal/biofilm interface. EPS are also implicated in increased resistance of biofilm cells to biocides and other antimicrobial compounds [9]. 

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