Constraints on mechanisms and rates of anaerobic oxidation of methane by microbial consortia: process-based modeling of ANME-2 archaea and sulfate reducing bacteria interactions
Constraints on mechanisms and rates of anaerobic oxidation of methane by microbial consortia: process-based modeling of ANME-2 archaea and sulfate reducing bacteria interactions
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DOI：
10.5194/bg-5-1587-2008
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发表时间：
2008-11
期刊：
影响因子：
4.9
通讯作者：
B. Orcutt;C. Meile
中科院分区：
文献类型：
--
作者：
B. Orcutt;C. Meile
抽象。甲烷的厌氧氧化（AOM）是去除地球海洋地下环境中产生的甲烷的主要过程。然而，AOM的生化机制仍然是难以捉摸的。通过明确解决所观察到的甲烷古菌和硫酸盐还原菌在财团介导AOM的空间排列，潜在的中间体参与的甲烷氧化和硫酸盐还原合作伙伴之间的电子转移进行了研究，通过财团规模的反应运输模型，集成了扩散运输的影响与热力学和动力学控制微生物活性。模型模拟用于评估约束不良的微生物特征的影响，例如维持代谢和细胞比速率的最低能量需求。环境条件的作用，如甲烷水平的影响的可行性H2，甲酸盐和乙酸盐作为中间物种，和中间物种的丰度对途径逆转的影响进行了研究。结果表明，较高的生产率的中间体通过AOM导致增加的扩散通量从甲烷氧化古菌硫酸盐还原菌，但可交换的物种的积累可以导致AOM的能量产量下降到低于ATP生产所需的。与实验室实验数据的比较表明，在Nauhaus等人（2007）的实验条件下，此处考虑的潜在中间体均无法支持与测量速率匹配的代谢活性。
Abstract. Anaerobic oxidation of methane (AOM) is the main process responsible for the removal of methane generated in Earth's marine subsurface environments. However, the biochemical mechanism of AOM remains elusive. By explicitly resolving the observed spatial arrangement of methanotrophic archaea and sulfate reducing bacteria found in consortia mediating AOM, potential intermediates involved in the electron transfer between the methane oxidizing and sulfate reducing partners were investigated via a consortium-scale reaction transport model that integrates the effect of diffusional transport with thermodynamic and kinetic controls on microbial activity. Model simulations were used to assess the impact of poorly constrained microbial characteristics such as minimum energy requirements to sustain metabolism and cell specific rates. The role of environmental conditions such as the influence of methane levels on the feasibility of H2, formate and acetate as intermediate species, and the impact of the abundance of intermediate species on pathway reversal were examined. The results show that higher production rates of intermediates via AOM lead to increased diffusive fluxes from the methane oxidizing archaea to sulfate reducing bacteria, but the build-up of the exchangeable species can cause the energy yield of AOM to drop below that required for ATP production. Comparison to data from laboratory experiments shows that under the experimental conditions of Nauhaus et al. (2007), none of the potential intermediates considered here is able to support metabolic activity matching the measured rates.