Microbial catabolic activities are naturally selected by metabolic energy harvest rate
Microbial catabolic activities are naturally selected by metabolic energy harvest rate
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DOI：
10.1038/ismej.2015.69
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发表时间：
2015-12-01
期刊：
影响因子：
11
通讯作者：
Rodriguez, Jorge
中科院分区：
文献类型：
--
作者：
Gonzalez-Cabaleiro, Rebeca;Ofiteru, Irina D.;Rodriguez, Jorge
产量和每单位底物能量收获率之间的基本权衡已被广泛讨论为微生物建立合作或竞争的主要特征。在这项研究中，这一点是通过开发一个通用的模型，模拟现有的和没有实验报告的微生物分解代谢活动之间的竞争，只定义基于众所周知的生化途径。没有考虑特定的微生物生理适应，生长产量计算耦合到catalysts能量学和一个共同的最大生物量特定catalysts率（表示为电子转移速率）被假定为所有微生物组。在这种方法下，成功的微生物代谢预测符合最大能量收获率的假设下的实验观察。模拟了两种通常在废水处理厂中发现的微生物生态系统，即：（i）葡萄糖的厌氧发酵和（ii）在好氧自养（硝化）和缺氧异养和自养（反硝化）条件下氮的氧化和还原。预测了实验观察到的葡萄糖发酵中的交叉补料，通过多个中间发酵途径，最终朝向甲烷和二氧化碳。类似地，两个阶段的硝化（铵和亚硝酸盐氧化剂）被预测为占主导地位的硝化在一个阶段。相反，反硝化作用在一个阶段中被预测（通过厌氧微生物）以及厌氧氨氧化（厌氧氨氧化）。模型的结果表明，这些意见是一个直接的后果，不同的能量产率每个电子转移在不同的步骤的途径。总的来说，我们的研究结果在理论上支持了这一假设，即成功的微生物分解代谢活动是由整体最大能量收获率选择的。
The fundamental trade-off between yield and rate of energy harvest per unit of substrate has been largely discussed as a main characteristic for microbial established cooperation or competition. In this study, this point is addressed by developing a generalized model that simulates competition between existing and not experimentally reported microbial catabolic activities defined only based on well-known biochemical pathways. No specific microbial physiological adaptations are considered, growth yield is calculated coupled to catabolism energetics and a common maximum biomass-specific catabolism rate (expressed as electron transfer rate) is assumed for all microbial groups. Under this approach, successful microbial metabolisms are predicted in line with experimental observations under the hypothesis of maximum energy harvest rate. Two microbial ecosystems, typically found in wastewater treatment plants, are simulated, namely: (i) the anaerobic fermentation of glucose and (ii) the oxidation and reduction of nitrogen under aerobic autotrophic (nitrification) and anoxic heterotrophic and autotrophic (denitrification) conditions. The experimentally observed cross feeding in glucose fermentation, through multiple intermediate fermentation pathways, towards ultimately methane and carbon dioxide is predicted. Analogously, two-stage nitrification (by ammonium and nitrite oxidizers) is predicted as prevailing over nitrification in one stage. Conversely, denitrification is predicted in one stage (by denitrifiers) as well as anammox (anaerobic ammonium oxidation). The model results suggest that these observations are a direct consequence of the different energy yields per electron transferred at the different steps of the pathways. Overall, our results theoretically support the hypothesis that successful microbial catabolic activities are selected by an overall maximum energy harvest rate.