Yokoyama Hiroshi, Moriya Naoko, Ohmori Hideyuki, Waki Miyoko, Ogino Akifumi, Tanaka Yasuo
Waste Recycling Research Team, National Institute of Livestock and Grassland Science, 2 Ikenodai, Tsukuba, Ibaraki, Japan.
Appl Microbiol Biotechnol. 2007 Nov;77(1):213-22. doi: 10.1007/s00253-007-1144-0. Epub 2007 Sep 8.
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.
变性梯度凝胶电泳（DGGE）和克隆文库分析，分析了极端嗜热条件下产氢厌氧微生物群落结构。通过在75℃下使用木糖、葡萄糖、乳糖、纤维二糖或可溶性淀粉作为底物，对牛粪进行反复分批培养，富集了极端嗜热微生物（ETM），其产氢量分别为每摩尔降解单糖0.56、2.65、2.17、2.68和1.73摩尔。DGGE和克隆文库分析结果一致，表明用四种基于己糖的底物（葡萄糖、乳糖、纤维二糖和可溶性淀粉）富集的ETM群落结构由单一物种组成，与产氢极端嗜热菌地下卡尔多厌氧菌密切相关，在亚种水平上具有多样性。用木糖富集的ETM比用其他底物富集的ETM多样性更高，并且包含与地下卡尔多厌氧菌相关的细菌和一种未分类的细菌，该细菌与降解木聚糖和产氢的极端嗜热菌嗜热热聚菌关系较远。
