Production and applications of microbial exopolysaccharides wall components but are either associated with surface macromolecules or are totally dissociated from the microbial cell. These are extracellular polysaccharides, also known as exopolysaccharides, and they show considerable diversity in their composition and structure Exopolysaccharides occur widely, especially among bacteria, and include free-living saprophytes and animal and plant pathogens. They are produced by most microalgae but relatively few yeasts and filamentous fungi produce exopolysaccharides. Although diversity plants produce a wide range of polysaccharides, their diversity is considerably less than those produced by micro-organisms. The number of different sugars found in olysaccharides is an indicator of diversity of structure and is eight fold higher(around 200)in those of microbial origin compared to those of plant origin Although exopolysaccharides do not normally have a structural role, they do form structures that can be detected by either t or electron microsco Exopolysaccharides may form part of a capsule closely attached to the microbial mUco Surface, or appear as loose slime secreted by the cell but not directly attached to it Exopolysaccharide producing cells usually form mucoid colonies on solid media and uid cultures of these cells may become very viscous. However growth conditions can fluence the composition, physical properties and organisation of exopolysaccharide 7.2.1 Composition Exopolysaccharides are mainly composed of carbohydrates(see Figure 7.1) common The sugars commonly found in microbial polysaccharides are extremely diverse and sugars include most of those found widely in animal and plant polysaccharides D-glucose D-galactose;> pyranose forms, ie D-mannose: · L-rhamnose; · L-fucose; However, whereas eukaryotic polysaccharides may contain pentoses such as D-xylose and D-ribose, they are only very rarely found in microbial polysaccharides Draw the ring structures of L-fucose(6-deoxy-L-galactose) and L-rhamnose (6-deoxy-l-mannose). Use the information in Figure 7.1 to help you do thisProduction and applications of microbial exopolysaccharides 195 wall components but are either associated with surface macromolecules or are totally dissociated from the microbial cell. These are extracellular polysaccharides, also known as exopolysaccharides, and they show considerable diversity in their composition and Structure. Exopolysaccharides occur widely, especially among bacteria, and include free-living saprophytes and animal and plant pathogens. They are produced by most microalgae but relatively few yeasts and filamentous fungi produce exopolysaccharides. Although plants produce a wide range of polysaccharides, their diversity is considerably less than those produced by micro-organisms. The number of different sugars found in polysaccharides is an indicator of diversity of structure and is eight fold higher (around 200) in those of microbial origin compared to those of plant origin. Although exopolysaccharides do not normally have a structural role, they do form structures that can be detected by either light or electron microscopy. Exopolysaccharides may form part of a capsule closely attached to the microbial cell surface, or appear as loose slime secreted by the cell but not directly attached to it. Exopolysaccharide producing cells usually form mucoid colonies on solid media and liquid cultures of these cells may become very viscous. However, growth conditions can influence the composition, physical properties and organisation of exopolysaccharide. dimity mucoid ~&nies 7.2.1 Composition Exopolysaccharides are mainly composed of carbohydrates (see Figure 7.1). The sugars commonly found in microbial polysaccharides are extremely diverse and include most of those found widely in animal and plant polysaccharides: common Sugars pyranose forms, ie e D-glucose; e D-mannose; furanose forms, ie e L-rhamnose; e L-fucose; However, whereas eukaryotic polysaccharides may contain pentoses such as D-xylose and D-ribose, they are only very rarely found in microbial polysaccharides. Draw the ring structures of L-fucose (6-deoxy-L-galactose) and L-rhamnose n (6-deoxy-1-mannose). Use the information in Figure 7.1 to help you do this