title: Methylobacterium sp. isolated from a Finnish paper machine produces highly pyruvated galactan exopolysaccharide.
abstract: The slime-forming bacterium Methylobacterium sp. was isolated from a Finnish paper machine and its exopolysaccharide (EPS) was produced on laboratory scale. Sugar compositional analysis revealed a 100% galactan (EPS). However, FT-IR showed a very strong peak at 1611 cm(-1) showing the presence of pyruvate. Analysis of the pyruvate content revealed that, based on the sugar composition, the EPS consists of a trisaccharide repeating unit consisting of D-galactopyranose and [4,6-O-(1-carboxyethylidene)]-D-galactopyranose with a molar ratio of 1:2, respectively. Both linkage analysis and 2D homo- and heteronuclear 1H and 13C NMR spectroscopy revealed the following repeating unit: -->3)-[4,6-O-(1-carboxyethylidene)]-alpha-D-Galp-(1-->3)[4,6-O-(1-carboxyethylidene)]-alpha-D-Galp-(1-->3)-alpha-D-Galp-(1-->. By enrichment cultures from various ground and compost heap samples a polysaccharide-degrading culture was obtained that produced an endo acting enzyme able to degrade the EPS described. The enzyme hydrolysed the EPS to a large extent, releasing oligomers that mainly consisted out of two repeating units.
authors.affiliation: Department of Agrotechnology and Food Sciences, Laboratory of Food Chemistry, Wageningen University, Bomenweg 2, 6703 HD Wageningen, The Netherlands.
authors.forename: René
authors.initials: R
authors.lastname: Verhoef
authors.forename: Pieter
authors.initials: P
authors.lastname: de Waard
authors.forename: Henk A
authors.initials: HA
authors.lastname: Schols
authors.forename: Matti
authors.initials: M
authors.lastname: Siika-aho
authors.forename: Alphons G J
authors.initials: AG
authors.lastname: Voragen
mesh_terms: D002240:Carbohydrate Sequence; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D005685:Galactans / Q000032:analysis / Q000737:chemistry*; D005690:Galactose / Q000031:analogs & derivatives* / Q000032:analysis; D008401:Gas Chromatography-Mass Spectrometry; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D020580:Methylobacterium / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010209:Paper; D011135:Polysaccharides, Bacterial / Q000737:chemistry*; D019289:Pyruvic Acid / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D000519:alpha-Galactosidase / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D005685:Galactans; D011135:Polysaccharides, Bacterial; C034485:4,6-pyruvylated galactose; D019289:Pyruvic Acid; D000519:alpha-Galactosidase; D005690:Galactose