Microbial exopolysaccharides: Main examples of synthesis, excretion, genetics and extraction

Characterization of Exopolysaccharides Produced by Rhizobia Species

“…Interest in the exploitation of microorganisms for production of valuable polysaccharides has greatly increased in recent years, since these biopolymers produced by a variety of microorganisms are chemically well defined and have attracted worldwide attention due to their novel and unique physical properties as bioadhesives, bioflocculants, biosorbents, gelling agents, probiotics, stabilizers, and thickeners, making them suitable for numerous commercial applications in the bionanotechnology, food, pharmaceutical, cosmetics, petroleum, civil construction, and environmental sectors. They have the advantages of being ecofriendly, non-toxic, and biodegradable (Freitas et al, 2011;Donot et al, 2012).…”

“…compounds are important in soil aggregation (Bomfeti et al, 2011). Rhizobial EPS can increase the adhesion of soil particles to plant roots and the mechanical stability of rhizospherical soils, and can also increase the level of water retention in this environment (Bomfeti et al, 2011;Donot et al, 2012).…”

“…Also, the repeating unit carries one to two succinyl groups located at the C-6 position of the seventh sugar residue, and a pyruvyl group linked to the eighth sugar residue through a 4, 6-ketal linkage (Chouly et al, 1995;Choi et al, 2012). Sinorhizobial polymers represent only a small fraction of the current polymer market (Donot et al, 2012). However, at this time, there is little physicochemical and industrial information available.…”

“…The galactoglucopolysaccharides obtained from Achromobacter spp., Agrobacterium radiobacter, pseudomonas marginalis, Rhizobium spp., Rhizobium sullea, and zooglea spp. have also been described (Donot et al, 2012;Gharzouli et al, 2013). In addition to sugar composition, types of linkages and non-sugar modification have already been described (Sutherland, 2001;Castellane and Lemos, 2007;Janczarek and Skorupska, 2011;Silvi et al, 2013;Castellane et al, 2014Castellane et al, , 2015.…”

“…In addition to sugar composition, types of linkages and non-sugar modification have already been described (Sutherland, 2001;Castellane and Lemos, 2007;Janczarek and Skorupska, 2011;Silvi et al, 2013;Castellane et al, 2014Castellane et al, , 2015. On the basis of monosaccharide composition in their backbone, bacterial EPS have been classified into homopolysaccharides and heteropolysaccharides (Donot et al, 2012). They are generally constituted by monosaccharides and non-carbohydrate substituents (such as acetate, pyruvate, succinate, and phosphate).…”