Denitrifying bacteria anaerobically oxidize methane in the absence of Archaea
Denitrifying bacteria anaerobically oxidize methane in the absence of Archaea
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DOI：
10.1111/j.1462-2920.2008.01724.x
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发表时间：
2008-11-01
影响因子：
5.1
通讯作者：
Strous, Marc
中科院分区：
文献类型：
--
作者：
Ettwig, Katharina F.;Shima, Seigo;Strous, Marc
最近，一种微生物菌群被证明可以将甲烷的厌氧氧化与反硝化偶联，主要是以亚硝酸盐还原为二氮气体的形式。这个聚生体主要由一个尚未确定特征的分支的细菌和甲烷古菌目的古菌所控制。目前的手稿报告的扩大富集文化，并解决了古菌在甲烷氧化的作用。对甲烷古菌和甲烷古菌的关键基因mcrA进行了测序。相关的辅因子F（430）被证明具有905 Da的质量，与产甲烷菌相同，与嗜甲烷古菌中发现的较重形式（951 Da）不同。经过长期富集（> 1年），在20 mM溴乙烷磺酸盐（MCR的特异性抑制剂）存在下，未观察到对厌氧甲烷氧化的抑制。如F（430）的荧光原位杂交和定量MALDI-TOF分析所示，培养条件的优化导致甲烷氧化速率更高，古细菌种群数量减少。质量平衡表明，甲烷氧化仍然耦合到亚硝酸盐还原在完全没有氧气。总之，我们的研究结果表明，细菌可以耦合甲烷的厌氧氧化反硝化，而不参与的厌氧微生物。
Recently, a microbial consortium was shown to couple the anaerobic oxidation of methane to denitrification, predominantly in the form of nitrite reduction to dinitrogen gas. This consortium was dominated by bacteria of an as yet uncharacterized division and archaea of the order Methanosarcinales. The present manuscript reports on the upscaling of the enrichment culture, and addresses the role of the archaea in methane oxidation. The key gene of methanotrophic and methanogenic archaea, mcrA, was sequenced. The associated cofactor F(430) was shown to have a mass of 905 Da, the same as for methanogens and different from the heavier form (951 Da) found in methanotrophic archaea. After prolonged enrichment (> 1 year), no inhibition of anaerobic methane oxidation was observed in the presence of 20 mM bromoethane sulfonate, a specific inhibitor of MCR. Optimization of the cultivation conditions led to higher rates of methane oxidation and to the decline of the archaeal population, as shown by fluorescence in situ hybridization and quantitative MALDI-TOF analysis of F(430). Mass balancing showed that methane oxidation was still coupled to nitrite reduction in the total absence of oxygen. Together, our results show that bacteria can couple the anaerobic oxidation of methane to denitrification without the involvement of Archaea.