Highly hydrolytic reuteransucrase from probiotic Lactobacillus reuteri strain ATCC 55730

Lactobacillus reuteri strain ATCC 55730 (LB BIO) was isolated as a pure culture from a Reuteri tablet purchased from the BioGaia company. This probiotic strain produces a soluble glucan (reuteran), in which the majority of the linkages are of the alpha-(1→4) glucosidic type (∼70%). This reuteran also contains alpha-(1→6)-linked glucosyl units...

Biochemical and molecular characterization of Lactobacillus reuteri 121 reuteransucrase

Lactobacillus reuteri strain 121 uses sucrose for synthesis of a unique, soluble glucan ('reuteran') with mainly α-(1→4) glucosidic linkages. The gene (gtfA) encoding this glucansucrase enzyme had previously been characterized. Here, a detailed biochemical and molecular analysis of the GTFA enzyme is presented. This is believed to be the first...

Glucan synthesis in the genus Lactobacillus: Isolation and characterization of glucansucrase genes, enzymes and glucan products from six different strains

Members of the genera Streptococcus and Leuconostoc synthesize various α-glucans (dextran, alternan and mutan). In Lactobacillus, until now, the only glucosyltransferase (GTF) enzyme that has been characterized is gtfA of Lactobacillus reuteri 121, the first GTF enzyme synthesizing a glucan (reuteran) that contains mainly α-(1 → 4) linkages...

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),...

Exploring and exploiting starch-modifying amylomaltases from thermophiles

Site-directed mutagenesis study of the three catalytic residues of the fructosyltransferases of Lactobacillus reuteri 121

Bacterial fructosyltransferases (FTFs) are retaining-type glycosidases that belong to family 68 of glycoside hydrolases. Recently, the high-resolution 3D structure of the Bacillus subtilis levansucrase has been solved [Meng, G. and Futterer, K., Nat. Struct. Biol. 10 (2003) 935-941]. Based on this structure, the catalytic nucleophile, general...

Efficient screening methods for glucosyltransferase genes in Lactobacillus strains

Limited information is available about homopolysaccharide synthesis in the genus Lactobacillus. Using efficient screening techniques, extracellular glucosyltransferase (GTF) enzyme activity, resulting in α-glucan synthesis from sucrose, was detected in various lactobacilli. PCR with degenerate primers based on homologous boxes of known...

Properties of the glucan branching enzyme of the hyperthermophilic bacterium Aquifex aeolicus

Kinetic properties of an inulosucrase from Lactobacillus reuteri 121

Inulosucrases catalyze transfer of a fructose moiety from sucrose to a water molecule (hydrolysis) or to an acceptor molecule (transferase), yielding inulin. Bacterial inulin production is rare and a biochemical analysis of inulosucrase enzymes has not been reported. Here we report biochemical characteristics of a purified recombinant...

Characterization of a novel fructosyltransferase from Lactobacillus reuteri that synthesis high-molecular-weight inulin and inulin oligosaccharides

Properties and applications of starch-converting enzymes of the alpha-amylase family

Starch is a major storage product of many economically important crops such as wheat, rice, maize, tapioca, and potato. A large-scale starch processing industry has emerged in the last century. In the past decades, we have seen a shift from the acid hydrolysis of starch to the use of starch-converting enzymes in the production of maltodextrin,...

Molecular characterization of a novel glucosyltransferase from Lactobacillus reuteri strain 121 synthesizing a unique , highly branched glucan with alpha-(1-4) and alpha-(1-6) glucosidic bonds

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...

Novel fructosyltransferases

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

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...

Turnover of dimethylsulfoniopropionate and dimethylsulfide in the marine environment: A mesocosm experiment

The production of dimethylsulfoniopropionate (DMSP) by marine phytoplankton and the fate of the produced DMSP and dimethylsulfide (DMS) were studied in 4 pelagic mesocosms during an algal bloom over a period of 1 mo. Bacterial numbers, concentrations of particulate and dissolved DMSP, DMS, and chlorophyll a were monitored, as well as the...