Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands.
Laboratory of Biochemistry, Wageningen University & Research, Wageningen, The Netherlands.
Appl Environ Microbiol. 2022 Jul 12;88(13):e0039122. doi: 10.1128/aem.00391-22. Epub 2022 Jun 14.
Syntrophic anaerobic consortia comprised of fatty acid-degrading bacteria and hydrogen/formate-scavenging methanogenic archaea are of central importance for balanced and resilient natural and manufactured ecosystems: anoxic sediments, soils, and wastewater treatment bioreactors. Previously published studies investigated interaction between the syntrophic bi-cultures, but little information is available on the influence of fermentative bacteria on syntrophic fatty acid oxidation, even though fermentative organisms are always present together with syntrophic partners in the above-mentioned ecosystems. Here, we present experimental observations of stimulated butyrate oxidation and methane generation by a coculture of Syntrophomonas wolfei with any of the following methanogens: Methanospirillum hungatei, Methanobrevibacter arboriphilus, or Methanobacterium formicicum due to the addition of a fermentative Trichococcus flocculiformis strain ES5. The addition of ES5 to the syntrophic cocultures led to an increase in the rates of butyrate consumption (120%) and volumetric methane production (150%). Scanning electron microscopy of the most positively affected coculture (S. wolfei, , and ES5) revealed a tendency of ES5 to aggregate with the syntrophic partners. Analysis of coculture's proteome with or without addition of the fermentative bacterium points to a potential link with signal transducing systems of , as well as activation of additional butyryl coenzyme A dehydrogenase and an electron transfer flavoprotein in S. wolfei. Results from the present study open doors to fascinating research on complex microbial cultures in anaerobic environments (of biotechnological and ecological relevance). Such studies of defined mixed populations are critical to understanding the highly intertwined natural and engineered microbial systems and to developing more reliable and trustable metabolic models. By investigating the existing cultured microbial consortia, like the ones described here, we can acquire knowledge on microbial interactions that go beyond "who feeds whom" relations but yet benefit the parties involved. Transfer of signaling compounds and stimulation of gene expression are examples of indirect influence that members of mixed communities can exert on each other. Understanding such microbial relationships will enable development of new sustainable biotechnologies with mixed microbial cocultures and contribute to the general understanding of the complex natural microbial interactions.
由脂肪酸降解细菌和氢/甲酸盐摄取产甲烷古菌组成的协同厌氧生物群落对于平衡和有弹性的自然和人工生态系统至关重要：缺氧沉积物、土壤和废水处理生物反应器。以前发表的研究调查了协同生物培养物之间的相互作用，但关于发酵细菌对协同脂肪酸氧化的影响的信息很少，尽管在上述生态系统中，发酵生物总是与协同伙伴一起存在。在这里，我们展示了发酵细菌 Trichococcus flocculiformis 菌株 ES5 的添加对协同培养物中 Syntrophomonas wolfei 与以下任何一种产甲烷菌（Methanospirillum hungatei、Methanobrevibacter arboriphilus 或 Methanobacterium formicicum）的协同丁酸氧化和甲烷生成的刺激作用的实验观察。向协同共培养物中添加 ES5 导致丁酸消耗率（120%）和体积甲烷生成率（150%）增加。对受影响最大的协同培养物（S. wolfei、和 ES5）的扫描电子显微镜观察显示，ES5 有与协同伙伴聚集的趋势。用或不用发酵细菌添加对共培养物的蛋白质组分析表明，与的信号转导系统以及 S. wolfei 中额外的丁酰辅酶 A 脱氢酶和电子传递黄素蛋白的激活存在潜在联系。本研究的结果为研究厌氧环境中复杂微生物培养物（具有生物技术和生态相关性）开辟了新的途径。对定义明确的混合种群的此类研究对于理解高度交织的自然和工程微生物系统以及开发更可靠和可信的代谢模型至关重要。通过研究现有的培养微生物群落，例如这里描述的那些，我们可以获得超越“谁喂养谁”关系的微生物相互作用的知识，但对相关各方都有益。信号化合物的转移和基因表达的刺激是混合群落成员可以相互施加的间接影响的例子。了解这种微生物关系将使我们能够利用混合微生物共培养物开发新的可持续生物技术，并有助于全面了解复杂的自然微生物相互作用。
