How do coal degrading methanogens make biogas? Unravelling central metabolism of Methermicoccus shengliensis

甲烷是地球上第二大温室气体。甲烷排放到大气中的主要来源是产甲烷古菌，强调了这些生物对全球碳循环和环境的重要性。虽然产甲烷菌已经研究了40多年，但最近发现了一种新的产甲烷途径：嗜热产甲烷菌高温球菌（M.）Shengliensis能够使用多种甲氧基化芳族化合物作为甲烷生成的底物，称为甲氧营养型甲烷生成。甲氧营养型产甲烷菌的发现与地球上大量的甲氧基化化合物如木质素的结合表明，甲氧营养型古菌可能在甲烷形成和全球碳循环中发挥了迄今为止被低估的作用。此外，M. Shengliensis代表了第一个具有从煤组分产生甲烷的潜力的微生物，这是关于微生物煤层甲烷产生的优化的重要发现。尽管这一杰出的古细菌的意义和新奇，但对其代谢的详细分析仍然缺失。我打算填补这一空白，通过研究转录组和蛋白质组学的反应与相关酶的酶学特征的甲氧基化芳烃上的增长沿着。此外，我还将分析M. Shengliensis和互养微生物聚生体，其需要多于一种微生物用于通过使用实验室规模的生物反应器降解甲氧基化化合物和形成甲烷。通过这种方法，我的目标是获得第一次洞察到M的生态重要性。shengliensis转化甲氧基化合物为甲烷的可能应用。Shengliensis在煤层气生产或石油生物降解中的应用。

Methane is the second most important greenhouse gas on earth. The main source of methane emission into the atmosphere are methanogenic archaea emphasizing the importance of those organisms for the global carbon cycle and the environment. Although methanogens have been studied for more than 40 years, a novel methanogenic pathway has recently been discovered: the thermophilic methanogen Methermicoccus (M.) shengliensis is able to use a large variety of methoxylated aromatic compounds as substrates for methane generation termed methoxydotrophic methanogenesis. Discovery of a methoxydotrophic methanogen in combination with the abundance of methoxylated compounds such as lignin on earth indicate that methoxydotrophic archaea might play a so far underestimated role in methane formation and the global carbon cycle. Moreover, M. shengliensis represents the first microorganism with the potential for methane generation from coal components which is an important finding with regard to the optimization of microbial coalbed methane generation. Despite the significance and novelty of this outstanding archaeon a detailed analysis of its metabolism is still missing. I intend to fill this gap by studying transcriptomic and proteomic responses to growth on methoxylated aromatics along with enzymological characterization of relevant enzymes. Furthermore, I will analyze the competition for methoxylated compounds between M. shengliensis and syntrophic microbial consortia that require more than one microorganism for the degradation of methoxylated compounds and formation of methane by use of laboratory scale bioreactors. With this approach I aim to get first insights into the ecological importance of M. shengliensis for conversion of methoxylated compounds to methane with regard to a possible application of M. shengliensis in coal bed methane production or biodegradation of oil.