pH as a Primary Control in Environmental Microbiology: 2. Kinetic Perspective
pH as a Primary Control in Environmental Microbiology: 2. Kinetic Perspective
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DOI：
10.3389/fenvs.2018.00101
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发表时间：
2018-09-25
影响因子：
4.6
通讯作者：
Kirk, Matthew F.
中科院分区：
文献类型：
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作者：
Jin, Qusheng;Kirk, Matthew F.
在一篇配套论文中，我们研究了微生物氧化还原反应对pH变化的热力学响应。在这里，我们将探讨这些热力学反应如何影响微生物群落的组成和功能。我们模拟丁酸互养氧化，硫酸盐还原，和甲烷的微生物财团在pH值范围从7到5。该模拟考虑了微生物代谢的热力学和微生物之间的相互作用。结果表明，pH值变化的热力学响应可以足够强，以加速或减缓微生物代谢。然后，这些动力学变化形成微生物相互作用的结果，包括微生物聚生体的成员资格和活性。此外，动力学变化调节碳通量和甲烷生产效率。模拟结果支持了环境pH可以通过改变氧化还原反应的能量产率来塑造微生物群落的组成和代谢功能的假设。它们也增加了目前的微生物生态学理论。具体而言，由于pH诱导的热力学响应，竞争性排斥的原理对于具有显著热力学限制的微生物过程失效，这允许在自然环境中竞争性呼吸反应的共同发生。总而言之，这些结果证实pH值是环境微生物学的主要控制因素。他们还强调了生态地球化学动力学模型在揭示和阐明环境参数与微生物群落之间的机制关系方面的可行性和潜力。
In a companion paper, we examined the thermodynamic responses of microbial redox reactions to pH changes. Here we explore how these thermodynamic responses may affect the composition and function of microbial communities. We simulate butyrate syntrophic oxidation, sulfate reduction, and methanogenesis by microbial consortia at pH ranging from 7 to 5. The simulation accounts for the thermodynamics of microbial metabolisms and the interactions among microbes. The results show that thermodynamic responses to variation in pH can be strong enough to speed up or slow down microbial metabolisms. These kinetic changes then shape the outcome of microbial interactions, including the membership and activity of microbial consortia. Moreover, the kinetic changes modulate carbon fluxes and the efficiency of methane production. The simulation results support the hypothesis that environmental pH can shape the composition and metabolic function of microbial communities by changing the energy yields of redox reactions. They also add to the current theories of microbial ecology. Specifically, due to pH-induced thermodynamic responses, the principle of competitive exclusion fails for microbial processes with significant thermodynamic limitations, which allows the co-occurrence of competing respiration reactions in natural environments. Taken together, these results confirm that pH is a primary control in environmental microbiology. They also highlight the feasibility and potential of biogeochemical kineticmodeling in uncovering and illuminatingmechanistic relationships between environmental parameters and microbial communities.