Goyal Nishu, Zhou Zhi, Karimi Iftekhar A
Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore.
School of Civil Engineering and Division of Environmental and Ecological Engineering, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN, 47907, USA.
Microb Cell Fact. 2016 Jun 10;15(1):107. doi: 10.1186/s12934-016-0500-0.
Methanococcus maripaludis is a rapidly growing, fully sequenced, genetically tractable model organism among hydrogenotrophic methanogens. It has the ability to convert CO2 and H2 into a useful cleaner energy fuel (CH4). In fact, this conversion enhances in the presence of free nitrogen as the sole nitrogen source due to prolonged cell growth. Given the global importance of GHG emissions and climate change, diazotrophy can be attractive for carbon capture and utilization applications from appropriately treated flue gases, where surplus hydrogen is available from renewable electricity sources. In addition, M. maripaludis can be engineered to produce other useful products such as terpenoids, hydrogen, methanol, etc. M. maripaludis with its unique abilities has the potential to be a workhorse like Escherichia coli and S. cerevisiae for fundamental and experimental biotechnology studies. More than 100 experimental studies have explored different specific aspects of the biochemistry and genetics of CO2 and N2 fixation by M. maripaludis. Its genome-scale metabolic model (iMM518) also exists to study genetic perturbations and complex biological interactions. However, a comprehensive review describing its cell structure, metabolic processes, and methanogenesis is still lacking in the literature. This review fills this crucial gap. Specifically, it integrates distributed information from the literature to provide a complete and detailed view for metabolic processes such as acetyl-CoA synthesis, pyruvate synthesis, glycolysis/gluconeogenesis, reductive tricarboxylic acid (RTCA) cycle, non-oxidative pentose phosphate pathway (NOPPP), nitrogen metabolism, amino acid metabolism, and nucleotide biosynthesis. It discusses energy production via methanogenesis and its relation to metabolism. Furthermore, it reviews taxonomy, cell structure, culture/storage conditions, molecular biology tools, genome-scale models, and potential industrial and environmental applications. Through the discussion, it develops new insights and hypotheses from experimental and modeling observations, and identifies opportunities for further research and applications.
沼泽红假单胞菌是氢营养型产甲烷菌中生长迅速、全基因组已测序且遗传操作易于处理的模式生物。它能够将二氧化碳和氢气转化为一种有用的清洁能源燃料（甲烷）。事实上，由于细胞生长时间延长，在以游离氮作为唯一氮源的情况下，这种转化作用会增强。鉴于温室气体排放和气候变化在全球的重要性，固氮作用对于从经过适当处理的烟道气中进行碳捕获和利用应用具有吸引力，因为在这些烟道气中可从可再生电源获得过剩的氢气。此外，可以对沼泽红假单胞菌进行基因工程改造，使其生产其他有用的产品，如萜类化合物、氢气、甲醇等。沼泽红假单胞菌凭借其独特的能力，有潜力成为像大肠杆菌和酿酒酵母那样用于基础和实验生物技术研究的主力生物。已有100多项实验研究探索了沼泽红假单胞菌二氧化碳和氮气固定的生物化学和遗传学的不同具体方面。其基因组规模代谢模型（iMM518）也已存在，用于研究基因扰动和复杂的生物相互作用。然而，文献中仍缺乏对其细胞结构、代谢过程和产甲烷作用的全面综述。本综述填补了这一关键空白。具体而言，它整合了文献中的分散信息，为诸如乙酰辅酶A合成、丙酮酸合成、糖酵解/糖异生、还原性三羧酸（RTCA）循环、非氧化戊糖磷酸途径（NOPPP）、氮代谢、氨基酸代谢和核苷酸生物合成等代谢过程提供完整而详细的视图。它讨论了通过产甲烷作用产生能量及其与代谢的关系。此外，它还综述了分类学、细胞结构、培养/储存条件、分子生物学工具、基因组规模模型以及潜在工业和环境应用。通过讨论，它从实验和模型观察中得出新的见解和假设，并确定进一步研究和应用的机会。
