title: Community analysis of hydrogen-producing extreme thermophilic anaerobic microflora enriched from cow manure with five substrates.
abstract: The present study analyzed the community structures of anaerobic microflora producing hydrogen under extreme thermophilic conditions by two culture-independent methods: denaturing gradient gel electrophoresis (DGGE) and clone library analyses. Extreme thermophilic microflora (ETM) was enriched from cow manure by repeated batch cultures at 75 degrees C, using a substrate of xylose, glucose, lactose, cellobiose, or soluble starch, and produced hydrogen at yields of 0.56, 2.65, 2.17, 2.68, and 1.73 mol/mol-monosaccharide degraded, respectively. The results from the DGGE and clone library analyses were consistent and demonstrated that the community structures of ETM enriched with the four hexose-based substrates (glucose, lactose, cellobiose, and soluble starch) consisted of a single species, closely related to a hydrogen-producing extreme thermophile, Caldoanaerobacter subterraneus, with diversity at subspecies levels. The ETM enriched with xylose was more diverse than those enriched with the other substrates, and contained the bacterium related to C. subterraneus and an unclassified bacterium, distantly related to a xylan-degrading and hydrogen-producing extreme thermophile, Caloramator fervidus.
authors.affiliation: Waste Recycling Research Team, National Institute of Livestock and Grassland Science, 2 Ikenodai, Tsukuba, Ibaraki, Japan. hiroshiy@affrc.go.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yokoyama
authors.forename: Naoko
authors.initials: N
authors.lastname: Moriya
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Ohmori
authors.forename: Miyoko
authors.initials: M
authors.lastname: Waki
authors.forename: Akifumi
authors.initials: A
authors.lastname: Ogino
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Tanaka
mesh_terms: D000818:Animals; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D002417:Cattle; D002475:Cellobiose / Q000378:metabolism; D048013:Acetivibrio thermocellus / Q000145:classification / Q000235:genetics / Q000378:metabolism; D017753:Ecosystem; D004591:Electrophoresis, Polyacrylamide Gel; D005947:Glucose / Q000378:metabolism; D006859:Hydrogen / Q000378:metabolism*; D007785:Lactose / Q000378:metabolism; D008372:Manure / Q000382:microbiology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013213:Starch / Q000378:metabolism; D013696:Temperature; D046950:Thermoanaerobacterium / Q000145:classification / Q000235:genetics / Q000378:metabolism; D014994:Xylose / Q000378:metabolism