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

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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.