Developing and Testing of Bioreactors for Methane Hydrate Biogeochemical Studies in the Laboratory

该技术开发项目针对甲烷水合物，这是地球上最丰富的碳氢化合物来源。几十年的地球化学研究已经确定了厌氧甲烷氧化（AMO）在含甲烷水合物的海洋沉积物中的重要性，但在碳循环中负责这一主要过程的生物从未被分离出来；目前还没有获得能够产生净AMO的纯培养微生物。该项目需要一个跨学科的综合实验和实地计划，通过在受控的可变定义实验室条件下跟踪AMO，确定AMO的机制，这些条件为微生物甲烷消耗提供了一个热力学有利的环境，而不是甲烷生产。为了创造支持AMO的条件，新设计的厌氧高压/低温生物反应器将被建造和测试。接种到生物反应器中的微生物来源将来自具有AMO活性的沉积物样品。这些沉积物将在俄勒冈海岸卡斯卡迪亚边缘的原位条件下回收。在生物反应器富集过程中，将对培养基和生成的甲烷水合物进行各种地球化学分析，并对环境的生物地球化学进行持续监测和表征。该生物反应器将为未来同位素标记生物地球化学平衡分析和动力学实验提供一个实验平台。

This technology development project addresses methane hydrates, which represent the most abundant hydrocarbon source on Earth. Decades of geochemical studies have established the importance of anaerobic methane oxidation (AMO) in methane hydrate containing marine sediments, but the organisms responsible for this major process in the Carbon cycle have never been isolated; and no pure cultures of microbes capable of net AMO have yet been obtained. The project entails an interdisciplinary integrated experimental and field program to determine the mechanism of AMO by following AMO under controlled variable-defined laboratory conditions that provide a thermodynamically favorable environment for microbial methane consumption over methane production. In order to create conditions which support AMO, newly designed anaerobic high pressure/low temperature bioreactors will be constructed and tested. The source of microorganisms inoculated into the bioreactors will come from sediment samples with AMO activity. These sediments will be recovered under in situ conditions from the Cascadia Margin off the Oregon coast. A variety of geochemical assays on the culture medium and the resulting methane hydrate will be performed during enrichments in the bioreactor, and the biogeochemistry of the environment will be continuously monitored and characterized. The bioreactors will provide an experimental platform for future analyses of isotopically labeled biogeochemical equilibrium and kinetic experiments under well defined controlled conditions.