Guzman Juan J L, Sousa Diana Z, Angenent Largus T
Biological and Environmental Engineering Department, Cornell University, Ithaca, NY, United States.
Laboratory of Microbiology, Wageningen University and Research, Wageningen, Netherlands.
Front Microbiol. 2019 Feb 5;10:110. doi: 10.3389/fmicb.2019.00110. eCollection 2019.
Syntrophic microbial partnerships are found in many environments and play critical roles in wastewater treatment, global nutrient cycles, and gut systems. An important type of syntrophy for the anaerobic conversion of carboxylic acids is H syntrophy. In this type of microbial partnership, dissolved H is produced by a bacterium and rapidly consumed by an archeon (methanogen), resulting in methane gas. This is referred to as interspecies H transfer, and some conversions rely on this mechanism to become thermodynamically feasible. For this reason, syntrophic partners are often not possible to separate in the lab, which hampers the full understanding of their physiology. Bioelectrochemical systems (BESs) may show promise to ultimately separate and study the behavior of the syntrophic bacterium by employing an abiotic H oxidation reaction at the anode, actively removing dissolved H. Here, we performed a proof-of-concept study to ascertain whether an H-removing anode can: (1) provide a growth advantage for the syntrophic bacterium; and (2) compete with the methanogenic partner. A mathematical model was developed to design a BES to perform competition experiments. Indeed, the operated BES demonstrated the ability to provide a growth advantage to the syntrophic bacterium compared to its methanogenic partner when grown in co-culture. Further, the BES provided the never-before isolated with a growth advantage compared to . Our results demonstrate a potential to use this BES to enrich H-sensitive syntrophic bacteria, and gives prospects for the development of an effective method for the separation of obligate syntrophs.
互营微生物伙伴关系存在于许多环境中，在废水处理、全球养分循环和肠道系统中发挥着关键作用。羧酸厌氧转化的一种重要互营类型是氢互营。在这种微生物伙伴关系中，一种细菌产生溶解态氢，而古菌（产甲烷菌）会迅速消耗它，从而产生甲烷气体。这被称为种间氢转移，一些转化过程依赖于这种机制才能在热力学上可行。因此，互营伙伴在实验室中通常无法分离，这妨碍了对它们生理特性的全面了解。生物电化学系统（BESs）可能有望通过在阳极采用非生物氢氧化反应来主动去除溶解态氢，从而最终分离并研究互营细菌的行为。在此，我们进行了一项概念验证研究，以确定去除氢的阳极是否能够：（1）为互营细菌提供生长优势；（2）与产甲烷伙伴竞争。我们开发了一个数学模型来设计一个用于进行竞争实验的生物电化学系统。事实上，运行的生物电化学系统表明，与产甲烷伙伴共培养时，它能够为互营细菌提供生长优势。此外，与……相比，生物电化学系统为从未被分离出来的……提供了生长优势。我们的结果表明，利用这种生物电化学系统富集对氢敏感的互营细菌具有潜力，并为开发一种分离专性互营菌的有效方法带来了希望。
