The effect of agave fructan products on the activity and composition of the microbiota determined in a dynamic in vitro model of the human proximal large intestine

Inulin and trans-galactooligosaccharides have so far fully met the criteria for prebiotics. This study shows the effect of putative prebiotics Metlos and Metlin (short and medium chain branched fructans from agave) on the activity and composition of the gut microbiota compared to the effects of two linear inulin type fructans (Synergy1 and...

Immunological Properties of Inulin-Type Fructans

Beneficial effects of inulin-type fructans are discussed in view of studies that applied the oligosaccharides in colon cancer, chronic inflammatory diseases, vaccination efficacy, and prevention of infection and allergy. In the present paper, we discuss their immunomodulating effects. It is suggested that immunomodulation is elicited through...

Different human gut models reveal the distinct fermentation patterns of arabinoxylan versus inulin

Different in vitro models have been developed to assess how food compounds affect the human gut microbiota. Using two such models (SHIME(R) and TIM-2), we compared how long-chain arabinoxylan (LC-AX), a wheat-derived potentially prebiotic fiber, and inulin (IN), a well-established prebiotic compound, modulate SCFA production and bifidobacteria...

Exo-inulinase of Aspergillus niger N402: A hydrolytic enzyme with significant transfructosylating activity

The purified exo-inulinase enzyme of Aspergillus niger N402 (AngInuE; heterologously expressed in Escherichia coli) displayed a sucrose:inulin (S/I) hydrolysis ratio of 2.3, characteristic for a typical exo-inulinase. The enzyme also had significant transfructosylating activity with increasing sucrose concentrations, producing various...

Structure-function relationships of glucansucrase and fructansucrase enzymes from lactic acid bacteria

Lactic acid bacteria (LAB) employ sucrase-type enzymes to convert sucrose into homopolysaccharides consisting of either glucosyl units (glucans) or fructosyl units (fructans). The enzymes involved are labeled glucansucrases (GS) and fructansucrases (FS), respectively. The available molecular, biochemical, and structural information on sucrase...

Single amino acid residue changes in subsite - 1 of inulosucrase from Lactobacillus reuteri 121 strongly influence the size of products synthesized

Bacterial fructansucrase enzymes belong to glycoside hydrolase family 68 and catalyze transglycosylation reactions with sucrose, resulting in the synthesis of fructooligosaccharides and/or a fructan polymer. Significant differences in fructansucrase enzyme product specificities can be observed, i.e. in the type of polymer (levan or inulin)...

Biochemical and molecular characerization of a levansucrase from Lactobacillus reuteri

Lactobacillus reuteri strain 121 employs a fructosyltransferase (FTF) to synthesize a fructose polymer [a fructan of the levan type, with β(2→6) linkages] from sucrose or raffinose. Purification of this FTF (a levansucrase), and identification of peptide amino acid sequences, allowed isolation of the first Lactobacillus levansucrase gene (lev),...

Purification of a novel fructosyltransferase from Lactobacillus reuteri strain 121 and characterization of the levan produced

Fructosyltransferase (FTF) enzymes have been characterized from various Gram-positive bacteria, but not from Lactobacillus sp. In a screening of 182 lactobacilli for polysaccharide production only one strain, Lactobacillus reuteri strain 121, was found to produce a fructan being a levan. Here we report the first-time identification and...

Functional food properties of non-digestible oligosaccharides: a consensus report from the ENDO project (DGXII AIRII-CT94-1095)

This paper results from the final phase of the ENDO project (DGXII AIRII-CT94-1095), a European Commission-funded project on non-digestible oligosaccharides (NDO). All participants in the programme met to perform a consensus exercise on the possible functional food properties of NDO. Topics studied during the project (including a workshop on...

Biochemical and structural characterization of the glucan and fructan exopolysaccharides synthesized by the Lactobacillus reuteri wild-type strain and by mutant strains

Lactobacillus reuteri LB 121 cells growing on sucrose synthesize large amounts of a glucan (D-glucose) and a fructan (D-fructose) with molecular masses of 3,500 and 150 kDa, respectively. Methylation studies and 13C or 1H nuclear magnetic resonance analysis showed that the glucan has a unique structure consisting of terminal, 4-substituted, 6...

Screening and characterization of Lactobacillus strains producing large amounts of exopolysaccharides

A total of 182 Lactobacillus strains were screened for production of extracellular polysaccharides (EPS) by a new method: growth in liquid media with high sugar concentrations. Sixty EPS-positive strains were identified; 17 strains produced more than 100 mg/l soluble EPS. Sucrose was an excellent substrate for abundant EPS synthesis. The ability...