title: Production of prebiotic galacto-oligosaccharides from lactose using beta-galactosidases from Lactobacillus reuteri.
abstract: The beta-galactosidases (beta-Gals) of Lactobacillus reuteri L103 and L461 proved to be suitable biocatalysts for the production of prebiotic galacto-oligosaccharides (GOS) from lactose. Maximum GOS yields were 38% when using an initial lactose concentration of 205 g/L and at approximately 80% lactose conversion. The product mixtures were analyzed by capillary electrophoresis (CE) and high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD). Disaccharides other than lactose and trisaccharides made up the vast majority of GOS formed. The main products were identified as beta-d-Galp-(1-->6)-d-Glc (allolactose), beta-d-Galp-(1-->6)-d-Gal, beta-d-Galp-(1-->3)-d-Gal, beta-d-Galp-(1-->6)-Lac, and beta-d-Galp-(1-->3)-Lac. There were no major products with beta1-->4 linkages formed. Both intermolecular and intramolecular transgalactosylation were observed. d-Galactose proved to be a very efficient galactosyl acceptor; thus, a relatively large amount of galactobioses was formed. Monosaccharides could be conveniently separated from the mixture by chromatography using a strong cation-exchange resin.
authors.affiliation: Research Centre Applied Biocatalysis, Petersgasse 14, A-8010 Graz, Austria.
authors.forename: Barbara
authors.initials: B
authors.lastname: Splechtna
authors.forename: Thu-Ha
authors.initials: TH
authors.lastname: Nguyen
authors.forename: Marlene
authors.initials: M
authors.lastname: Steinböck
authors.forename: Klaus D
authors.initials: KD
authors.lastname: Kulbe
authors.forename: Werner
authors.initials: W
authors.lastname: Lorenz
authors.forename: Dietmar
authors.initials: D
authors.lastname: Haltrich
mesh_terms: D002236:Carbohydrate Conformation; D002851:Chromatography, High Pressure Liquid; D019075:Electrophoresis, Capillary; D005690:Galactose / Q000378:metabolism*; D052200:Limosilactobacillus reuteri / Q000201:enzymology*; D007785:Lactose / Q000378:metabolism; D009844:Oligosaccharides / Q000096:biosynthesis*; D019936:Probiotics; D001616:beta-Galactosidase / Q000378:metabolism*
chemical_list: D009844:Oligosaccharides; D001616:beta-Galactosidase; D007785:Lactose; D005690:Galactose