Exopolysaccharide and Kestose Production by Lactobacillus sanfranciscensis LTH2590

Abstract

The effect was investigated of sucrose concentration on sucrose metabolism and on the formation of exopolysaccharide (EPS) by Lactobacillus sanfranciscensis LTH2590 in pH-controlled fermentations with sucrose concentrations ranging from 20 to 160 g liter ؊1 . The EPS production increased and the relative sucrose hydrolysis activity decreased by increasing the sucrose concentration in the medium. The carbon recovery decreased from 95% at a sucrose concentration of 30 g liter ؊1 to 58% at a sucrose concentration of 160 g liter ؊1 because of the production of an unknown metabolite by L. sanfranciscensis. This metabolite was characterized as a fructo-oligosaccharide. The oligosaccharide produced by L. sanfranciscensis was purified and characterized as a trisaccharide with a glucose/fructose ratio of 1:2. The comparison of the retention time of this oligosaccharide and that of pure oligosaccharide standards using two different chromatography methods revealed that the oligosaccharide produced by L. sanfranciscensis LTH2590 is 1-kestose. Kestose production increased concomitantly with the initial sucrose concentration in the medium.Polysaccharides of plant origin have being used for a long time in the food industry as biothickeners, texture stabilizers, or gelling agents. In the last decades several microbial exopolysaccharides (EPS) have been described as alternatives for plant polysaccharides. Microbial polysaccharides have rheological properties that match the industrial demands and can be produced in large amounts and at high purities. The interest of the food industry in developing multifunctional additives that not only provide the desired improvement of the texture but also have additional nutritional properties led to extensive search for polysaccharides with prebiotic attributes. Prebiotics are nondigestible food ingredients that affect the host beneficially by selectively stimulating the growth and/or activity of specific bacteria in the colon and thus improve host health (12). Fructo-oligosaccharides (FOS), xylo-oligosaccharide, and inulin are some of the prebiotics available for human consumption (5, 24). FOS with prebiotic properties (e.g., kestose and nystose) are polymers of D-fructose joined by ␤(231) linkages and terminated with a D-glucose molecule linked to fructose by an ␣(132) bond as in sucrose (22). The degree of polymerization can vary from 2 to 35. FOS with a degree of polymerization of 3 to 5 are called neosugars (30) and can be enzymatically synthesized from sucrose by using fructosyltransferase from Aspergillus niger (16,17). Mckellar and Modler (23) showed that the maximum activity of ␤-fructosidase, responsible for the hydrolysis of inulin-type polysaccharides by bifidobacteria, was observed with neosugars.Lactic acid bacteria (LAB) are widely used for the production of numerous fermented foods and are generally recognized as safe. Several EPS-producing LAB such as Lactobacillus delbrueckii subsp. bulgaricus, Lactococcus lactis, and Streptococcus thermophilus have been isolated from ferme...

The levansucrase and inulosucrase enzymes of Lactobacillus reuteri 121 catalyse processive and non-processive transglycosylation reactions

“…The ability of levansucrase enzymes to synthesize b(2R1)-as well as b(2R6)-linked FOSs has been reported elsewhere (Euzenat et al, 2005;Támbara et al, 1999;Korakli et al, 2003). Lb.…”

“…This suggests that the growing polymer chain remains bound to the enzyme, and that fructan-chain elongation proceeds via a processive type of reaction. In contrast, the enzymes of Gluconacetobacter diazotrophicus, Zymomonas mobilis and Lactobacillus sanfranciscensis have been found to synthesize mainly short fructooligosaccharides (FOSs; kestose and nystose) from sucrose (Doelle et al, 1993;Hernández et al, 1995;Korakli et al, 2001Korakli et al, , 2003; thus, these enzymes may employ a nonprocessive type of reaction, involving release of the fructan chain after (virtually) each fructosyl transfer. The available three-dimensional structures of the B. subtilis SacB levansucrase, which synthesizes mainly large polymers, and the FOS-synthesizing levansucrase from G. diazotrophicus (Martinez-Fleites et al, 2005;Meng & Futterer, 2003), show that the active-site architecture of both levansucrase enzymes is identical (Martinez-Fleites et al, 2005;Meng & Futterer, 2003).…”

Screening for gum‐producing Lactic acid bacteria in Oil palm (Elaeis guineensis) and raphia palm (Raphia regalis) sap from South‐West Nigeria

“…The highest exopolysaccharide producing isolate strain was L. plantarum (810.75 mg/L) whereas, the least exopolysaccharide producing isolate was L. crispatus (242.5 mg/L). The values obtained for EPS production and cell dry weight were comparable with data obtained in previous experiments with lactic acid bacteria species/strains (Cerning, 1990; Cerning, Bouillanne, Landon, & Desmazeaud, 1992; Korakli et al., 2003; Minervini et al., 2010; Mozzi, Savoy de Giori, Oliver, & Font de Valdez, 1996; Vogel, 2008). Other studies have also reported that some microorganisms are capable of producing and excreting over 40 g/L of EPSs under conditions of stress (Lin & Cheng‐Chien, 2007; Papinutti, 2010; Ravella et al., 2010).…”

“…The low yields EPSs production by majority of LAB species has reduced their commercial viability and limited industrial applications. Studies have showed that some LAB species have potentials to produce high yields EPSs roughly 40 g/L (Kaditzky & Vogel, 2008; Korakli, Pavlovic, Ganzle, & Vogel, 2003; Minervini et al., 2010). Industrial applications of natural polymers for various uses have increased their demand and this has led to an increased attention toward exopolysaccharides and this has re‐enforced the search for LAB strains with potentials for production of high yields EPS.…”

Binding Interactions Between α-glucans from Lactobacillus reuteri and Milk Proteins Characterised by Surface Plasmon Resonance

“…By contrast HoPS were reported to be produced in considerably larger amounts up to 40 gL -1 . 6 Leuconostoc and Lactobacillus species form HoPS in the presence of sucrose. 3 A variety of Lactobacillus reuteri strains synthesise fructans and glucans with differing molecular properties, e.g.…”