LExEn: Diversity of Electron Donors and Electron Acceptors Supporting the Growth of Hyperthermophilic Microorganisms.

[00:8536 . 56]可爱的微生物被认为对高温（80-110摄氏度）、缺氧环境的地球化学有重要影响，比如地球表面深处、海洋底部和陆地温泉周围的环境。本研究的目的是评估厌氧超嗜热微生物的代谢多样性，以便更多地了解热微生物生态系统中可能发生的生物地球化学过程。据推测，有多种微生物能够通过氧化有机化合物，如：醋酸酯和其他短链脂肪酸、长链脂肪酸、氨基酸、芳香族化合物和各种碳氢化合物，在炎热的环境中生存。预计这些有机化合物氧化的电子受体包括铁（III）、硫酸盐、S（零）或硝酸盐。有人提出，在没有这些电子受体的情况下，这些有机化合物可以被微生物转化为甲烷。将采用新的策略来尝试恢复自养，氢氧化，铁（III）还原的超嗜热微生物，因为假设一些具有这种呼吸形式的生物体将在系统发育上属于地球上仍然存在的分支最深的微生物。为了评估铁（III）还原剂在高温酸性环境中可能具有活性的可能性，将尝试恢复可以还原在低ph下发现的可溶性铁（III）的嗜酸型超嗜热菌。铁（III）还原型超嗜热菌产生同位素独特的铁（II）矿物的可能性将通过检查这些矿物中的氧和铁同位素来评估。预计这些研究将进一步深入了解地球上热微生物生态系统的生物学和地质学，以及其他行星热地下可能存在的微生物生态系统。这些研究还有望通过以下方面产生经济效益：1)更好地解释具有重要经济意义的矿床的生成；2)为有毒有机和金属污染物的修复提供新策略；3)提出了提高油气采收率的新途径。

0085365LovelyMicroorganisms are thought to have an important impact on the geochemistry of hot (80-110 degrees C), oxygen-depleted environments such as those found deep below the Earth's surface, at the bottom of the ocean, and around terrestrial hot springs. The goal of this research is to evaluate the metabolic diversity of anaerobic hyperthermophilic microorganisms in order to learn more about the biogeochemical processes that are possible in hot microbial ecosystems. It is hypothesized that there is wide diversity of microorganisms that are capable of living in hot environments by oxidizing organic compounds such as: acetate and other short-chain fatty acids, long-chain fatty acids, amino acids, aromatic compounds, and a variety of hydrocarbons. Electron acceptors for the oxidation of these organic compounds are predicted to include Fe(III), sulfate, S (zero), or nitrate. It is proposed that in the absence of these electron acceptors that these organic compounds can be microbially converted to methane. Novel strategies will be employed in an attempt to recover autotrophic, hydrogen-oxidizing, Fe(III)-reducing hyperthermophiles because it is hypothesized that some organisms with this form of respiration will phylogenetically be among the most deeply branching microorganisms still existing on Earth. In order to evaluate the possibility that Fe(III) reducers may be active in hot, acidic environments, an attempt will be made to recover acidophilic hyperthermophiles that can reduce the soluble Fe(III) found at low pH. The possibility that Fe(III)-reducing hyperthermophiles produce isotopically unique Fe(II) minerals will be evaluated by examining the oxygen and iron isotopes in these minerals. It is expected that these studies will provide further insight into the biology and geology of hot microbial ecosystems on Earth as well as the microbial ecosystems that may exist in the hot subsurface of other planets. These studies are also expected to have economic benefits by: 1) better explaining the generation of economically important ore deposits; 2) providing new strategies for the remediation of toxic organic and metal contaminants; and 3) suggesting a new approach for increased recovery of hydrocarbons from petroleum reservoirs.