Promising biotechnological applications of antibiofilm exopolysaccharides

Abstract

Polysaccharides are polymers of carbohydrates with anenormous structural diversity, from long linear repetition ofthe same monomer to highly branched structures of dif-ferent sugars. This high structural diversity reflects thefunctional diversity of these molecules. There are twotypes of polysaccharides, storage polysaccharides (i.e.glycogen) and structural polysaccharides, which are nor-mally secreted by the cell and form different cell structures(i.e. cellulose, chitin). Extracellular polysaccharides orexopolysaccharides belong to this last group.Exopolysaccharides are produced not only by microor-ganisms, but also by algae, plants and animals (Suther-land, 2005). Bacterial exopolysaccharides are a majorcomponent of the extracellular polymeric substance(EPS) or matrix of biofilms, and mediate most of thecell-to-cell and cell-to-surface interactions required forbiofilm formation and stabilization (Flemming and Win-gender, 2010). The matrices of biofilms from natural envi-ronments, such as marine and fresh water, soil, or chronicinfections, contain a ubiquitous composition of polysac-charides. More than 30 different matrix polysaccharideshave been characterized so far. Several are homopoly-saccharides (i.e. glucans, fructans, cellulose), but most ofthese are heteropolysaccharides consisting on a mixtureof sugar residues. Exopolysaccharides can even differbetween strains of single species, as exemplified bystrains of