Hydrated EPS

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Extracellular polymeric substances (EPS) are a heterogeneous matrix of polymers comprised of mainly polysaccharides, proteins, lipids and nucleic acids (McSwain et al., 2005; Mishra and Jha, 2013). EPS are produced in two forms, either associated with the cell surface in capsular form (Sutherland, 1990) or loosely bound to the cell surface as slime polysaccharides (Suresh Kumar et al., 2007). The composition of EPS synthesised varies significantly and thus affecting the physico-chemical properties. Some of the EPS are neutral, but majority are polyanionic (Sutherland, 2001). In addition, the contents of carbohydrates, proteins and nucleic acids was found to have substantial effect on the flocculation of bacteria (Sheng et al., 2005). EPS are synthesized intracellularly either throughout growth, late-exponential or stationary stage (Mishra and Jha, 2013). The rate of production …show more content…

The formation of hydrated EPS layer surrounding a microorganism will provide protection against desiccation and predation (Suresh Kumar et al., 2007). Furthermore, EPS plays a principal role in cell aggregates formation and initiation of flocculation as well as biofilms. The production of EPS not only involves in anchoring of biofilms to hydrophobic surfaces but also accumulation of recalcitrant PAHs by sorption to exopolymer (Johnsen et al., 2005). This properties are significant to in removal of water pollutant (Singh et al., 2006) and selective plugging in MEOR (Sen, 2008). As a key constituent in cell floc and biofilm formation, EPS helps to facilitate the mechanism of cell adhesion to surfaces and other organisms, as well as uptake of nutrients (Laspidou and Rittmann, 2002). The EPS matrix in biofilm displays as a medium for biochemical interaction among cells in microbial aggregates (Laspidou and Rittmann, 2002). Besides that, EPS can also function as emulsifier and surfactants that are

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