Similar gaps of knowledge exist with respect to the chemical composition and specific roles of the macromolecules secreted by Bacillus subtilis in its natural environment.

In find more this review, the different EPS from B. subtilis were classified into four main functional categories: structural (neutral polymers), sorptive (charged polymers), surface-active and active polymers. In addition, current information regarding the genetic expression, production and function of the main polymers secreted by B. subtilis strains, particularly those related to biofilm formation and its architecture, has been compiled. Further characterization of these EPS from B. subtilis remains a challenge. Microbial exopolymeric substances (EPS) include a wide diversity of molecules released

by microorganisms in their natural environment as well as under laboratory conditions Everolimus supplier (Flemming et al., 2004; Dupraz & Visscher, 2005; Aguilar et al., 2007). Although initially the term EPS was used to describe extracellular polysaccharides, recent studies have revealed that these matrixes are more complex, including lipopolysaccharides, glycolipids, lipids, proteins or peptides and nucleic acids (Wingender et al., 1999; Decho, 2000). This complex structure comprises the exopolymeric matrix in which cells are embedded, and is also referred to as the biofilm (O’Toole & Ghannoum, 2004). The chemical composition of the EPS depends on the genetics of the microbial cells and the physicochemical environment in which the biofilm matrix develops (Sutherland, 2001a). Consequently, environmental conditions ultimately dictate the key properties of the biofilms such as porosity, density, water content, charge, sorption and ion exchange properties, hydrophobicity and mechanical stability (Wingender et al., 1999). Substances associated with exopolymeric matrices Idoxuridine have multiple functions. Some serve as signaling molecules or messengers and others are energy and nutrient reserves with an important role in polymer degradation

and surface adhesion (O’Toole & Ghannoum, 2004; Decho et al., 2010). Recently, the polyelectrolytic nature of some of these molecules has been described with concomitant use in the fabrication of nanowires (Dobrynin, 2008; Lovley, 2008). Although EPS are common to bacteria and critical in cell survival, they are relatively poorly studied, especially with respect to the matrix composition in natural environments (Davey & O’Toole, 2000). In this review, some of the current information on the EPS of Bacillus subtilis is compiled. The role of these molecules within natural environment is also discussed. The focus is on B. subtilis because it is ubiquitous, present in almost all ecosystems and the EPS produced by this organism have significant ecological relevance with respect to cell survival and differentiation within a biofilm (Earl et al., 2008). As shown in Supporting Information, Table S1, a wide variety of EPS are secreted by B.