title: Isolation of dextran-hydrolyzing intestinal bacteria and characterization of their dextranolytic activities.
abstract: The aim of this study was to isolate dextran-hydrolyzing bacteria from the human intestines and to identify their dextranolytic enzymes. For this, dextranase-producing microorganisms were screened from fecal samples by using blue dextran-containing media. Colonies producing a decolorized zone were isolated and they were grouped using RAPD-PCR. 16S rRNA gene sequencing analysis revealed the isolates were Bacteroides (B.) thetaiotaomicron, B. ovatus, B. vulgatus, B. dorei, B. xylanisolvens, B. uniformis, and Veillonella (V.) rogosae. Thin layer chromatography analysis showed that the dextranases exhibit mainly endo-type activity and produce various oligosaccharides including isomaltose and isomaltotriose. Zymogram analysis demonstrated that enzymes localized mainly in the cell membrane fraction and the molecular weight was 50-70 kDa. When cultured in a dextran-containing medium, all strains isolated in this study produced short-chain fatty acids, with butyric acid as the major compound. This is the first study to report that human intestinal B. xylanisolvens, B. dorei, and V. rogosae metabolize dextran utilizing dextranolytic enzymes.
authors: Division of Animal, Horticultural, and Food Sciences, Brain Korea 21 Center for Bio-Resource Development, Chungbuk National University, Cheongju, 361-763, Republic of Korea.
authors: Jin Kyoung
authors: JK
authors: Kim
authors: So-Yeon
authors: SY
authors: Shin
authors: Jin Seok
authors: JS
authors: Moon
authors: Ling
authors: L
authors: Li
authors: Seung Kee
authors: SK
authors: Cho
authors: Tae-Jip
authors: TJ
authors: Kim
authors: Nam Soo
authors: NS
authors: Han
mesh_terms: D001419:Bacteria / Q000378:metabolism*; D003910:Dextranase / Q000378:metabolism; D003911:Dextrans / Q000378:metabolism*; D006801:Humans; D007422:Intestines / Q000382:microbiology*; D009844:Oligosaccharides / Q000378:metabolism
chemical_list: D003911:Dextrans; D009844:Oligosaccharides; D003910:Dextranase
keywords: bacteroidetes; dextran; dextran-oligosaccharides; dextranase; intestinal bacteria