Diender Martijn, Pereira Ricardo, Wessels Hans J C T, Stams Alfons J M, Sousa Diana Z
Laboratory of Microbiology, Wageningen University Wageningen, Netherlands.
Department of Laboratory Medicine, Radboud University Medical Center Nijmegen, Netherlands.
Front Microbiol. 2016 Jul 4;7:1049. doi: 10.3389/fmicb.2016.01049. eCollection 2016.
Hydrogenotrophic methanogenic archaea are efficient H2 utilizers, but only a few are known to be able to utilize CO. Methanothermobacter thermoautotrophicus is one of the hydrogenotrophic methanogens able to grow on CO, albeit about 100 times slower than on H2 + CO2. In this study, we show that the hydrogenotrophic methanogen Methanothermobacter marburgensis, is able to perform methanogenic growth on H2/CO2/CO and on CO as a sole substrate. To gain further insight in its carboxydotrophic metabolism, the proteome of M. marburgensis, grown on H2/CO2 and H2/CO2/CO, was analyzed. Cultures grown with H2/CO2/CO showed relative higher abundance of enzymes involved in the reductive acetyl-CoA pathway and proteins involved in redox metabolism. The data suggest that the strong reducing capacity of CO negatively affects hydrogenotrophic methanogenesis, making growth on CO as a sole substrate difficult for this type of methanogens. M. marburgensis appears to partly deal with this by up-regulating co-factor regenerating reactions and activating additional pathways allowing for formation of other products, like acetate.
嗜氢产甲烷古菌是高效的氢气利用者，但已知只有少数能够利用一氧化碳。嗜热自养甲烷杆菌是能够在一氧化碳上生长的嗜氢产甲烷菌之一，尽管其生长速度比在氢气 + 二氧化碳上慢约100倍。在本研究中，我们表明嗜氢产甲烷菌马尔堡甲烷杆菌能够在氢气/二氧化碳/一氧化碳以及一氧化碳作为唯一底物的条件下进行产甲烷生长。为了进一步深入了解其羧营养代谢，我们分析了在氢气/二氧化碳和氢气/二氧化碳/一氧化碳条件下生长的马尔堡甲烷杆菌的蛋白质组。在氢气/二氧化碳/一氧化碳条件下培养的菌株显示，参与还原性乙酰辅酶A途径的酶和参与氧化还原代谢的蛋白质相对丰度较高。数据表明，一氧化碳的强还原能力对嗜氢产甲烷作用产生负面影响，使得这类产甲烷菌难以将一氧化碳作为唯一底物进行生长。马尔堡甲烷杆菌似乎通过上调辅因子再生反应和激活其他允许形成其他产物（如乙酸盐）的途径来部分应对这一问题。
