Redirecting the carbon flux by implementing energy-conserving modules in Methanothermobacter thermautotrophicus to capture carbon dioxide

可再生能源是许多国家电力组合中公认的一部分。然而，生产和消费之间的不平衡使得储存多余的可再生电力变得必要。氢气(H2)可以通过可再生能源电解水来产生。在生物甲基化发电制气过程中，利用氢气从二氧化碳(CO2)制备甲烷气(CH4)已经成为克服直接储存氢气成本的一种解决方案。嗜热产甲烷古生菌的纯培养，如甲烷热营养杆菌，用于将CO2和H2转化为CH4，具有较高的过程稳定性和产率。由此产生的可再生天然气中含有97%的甲烷。只需很少的额外调节，这种气体就可以引入现有的天然气电网，具有巨大的存储容量和巨大的分配可能性。我的实验室已经开发了一种嗜热营养分枝杆菌的遗传系统，现在可以通过研究和优化生物催化剂的微生物生理学，并以动力转化为化学物质的方法拓宽产品谱，来利用这种生物技术的全部潜力。在现有遗传系统的基础上，我们将开发更多的工具，例如，在嗜热营养分枝杆菌中生产标记酶变体。这将使我们能够研究与甲烷生成高度相关的酶的生物化学。为此，我们将与美国和澳大利亚的合作伙伴合作。基因工具，结合稳态发酵和系统生物学数据，将被用来优化嗜热营养分枝杆菌的新陈代谢，以生产作为概念验证产品的乙酸乙酯。例如，乙酸乙酯作为风味增强剂、化妆品成分和2，3-丁二醇等其他平台化学品的前体具有经济价值。我的实验室还开发了一个基因组规模的新陈代谢模型，它提供了在湿实验室实验之前用硅胶测试假说的平台。我们已经使用该模型来模拟代谢变化，这些变化可能导致更高的乙酰胆碱通量，这将在本提案中进行测试。在此基础上，我们将证明嗜热营养分枝杆菌可以作为一个坚硬的微生物底盘，在一个化学动力平台上生产其他生物技术相关的产品。

Renewable energy sources are well-established parts of the electricity mix for many countries. However, an imbalance between production and consumption makes storing surplus renewable electric power necessary. Hydrogen (H2) can be generated through the electrolysis of water with renewable energy. Using H2 to produce methane gas (CH4) from carbon dioxide (CO2) in a power-to-gas process with biomethanation has already become a solution to overcome the costly direct storage of H2. Pure cultures of thermophilic methanogenic archaea, such as Methanothermobacter thermautotrophicus, are applied to convert CO2 and H2 into CH4 with high process stability and production rates. The resulting renewable natural gas contains >97% CH4. With only little additional conditioning, this gas can be introduced into the existing natural gas grid, with vast storage capacity and great distribution possibilities. My lab has developed a genetic system for M. thermautotrophicus, which can now be utilized to harness the full potential of this biotechnology by investigating and optimizing the microbial physiology of the biocatalyst and broadening the product spectrum in a power-to-chemicals approach. Based on the available genetic system, we will develop additional tools, for example, to produce tagged enzyme variants in M. thermautotrophicus. This will allow us to study the biochemistry of highly relevant enzymes for methanogenesis. For this purpose, we will collaborate with partners in the US and Australia. The genetic tools, in combination with steady-state fermentation and systems biology data, will be exploited to optimize the metabolism of M. thermautotrophicus to produce acetoin as a proof-of-concept product. For example, acetoin is of economic value as a flavor enhancer, cosmetics ingredient, and precursor to further platform chemicals such as 2,3-butanediol. My lab has also developed a genome-scale metabolic model, which provides the platform to test hypotheses in silico before wet lab experiments. We have used the model to simulate metabolic changes that could lead to higher flux toward acetoin, which will be tested in this proposal. With this, we will demonstrate that M. thermautotrophicus can be utilized as a rigid microbial chassis to produce other biotechnologically relevant products in a power-to-chemicals platform.