Recent advances in endophytic exopolysaccharides: Production, structural characterization, physiological role and biological activity

Production and partial characterization of extracellular polysaccharide from endophytic Bacillus cereus RCR 08

“…Majority of the isolates were poor to moderate producers with the exception of isolate RCR 08, which produced good amount of EPS (1.5 g/L) and was selected for further studies. Liu et al (2017) in a recent review have summarized the EPS-producing endophytic bacteria and their host plants which include rice, sorghum, sugarcane, Artimisia annua, Ophiopogon japonicas, etc. Morphological and physiological analysis revealed that the endophytic isolate RCR 08 endophytic to root tissues of R. communis L. is a rod-shaped, Gram-positive, motile and endospore forming bacterium which form white smooth colonies on mineral salts agar ( Figure 1).…”

“…(Wingender et al, 1999) are biosynthesized by bacteria and fungi via intracellular or extracellular processes (Freitas et al, 2011). In recent years, a variety of structurally different EPSs with bioactive potentials have been reported from endophytes (Guo et al, 2014;Mahapatra and Banerjee, 2016;Liu et al, 2017 ).…”

Structural analysis and characterization of a clinically important low molecular weight natural dextran synthesized by Leuconostoc lactis KU665298 dextransucrase

“…Some dextrans have -(1, 2) or -(1,4) branch linkages, depending on the bacterial source. The exact structure of each type of dextran depends on the degree of branching, involving -(1, 2), -(1,3) and -(1, 4) linkages (Seymour and Knapp, 1980), which depends on the specific microbial strain and, hence, on the specificity of dextransucrase involved (Jeanes et al, 1954;Purama et al, 2009;Bai et al, 2016;Liu et al, 2017). In order to gain a better understanding of physicochemical, structural, and rheological parameters of the dextran, the present study focused on the production of dextran by employing L. lactis dextransucrase and characterization of purified dextran.…”

“…Dextran is an example of bacterial homopolysaccharide composed of D-glucose and largely of -1,6-glucopyranosidic linkages in the main chain (Naessens et al, 2005;Vettori et al, 2012;Liu et al, 2017;Nacher-Vazquez et al, 2017). Lactic acid bacteria have a long history of safe use in human consumption and, therefore, among variety of microorganisms, are most widely explored for the production of microbial exopolysaccharides (Nikolic et al, 2012).…”

“…The exploration of new isolates is important because the characteristics of dextran varies from species to species. The high demand and low available amount of dextrans has led to the catalytic synthesis by dextransucrase enzyme.The molecular structure and conformation of dextran are important in determining its bioactivities, which became the focus in recent years (Chen et al, 2016;Liu et al, 2017). Physical and chemical properties, such as solubility, viscosity, specific rotation, molecular weight and linkages can undergo variations depending on the different dextransucrases produced by different strains of bacteria (Purama, et al, 2009;Bai et al, 2016;Zhang et al, 2016;Guzman et al, 2018).…”