Mechanistic investigations of the syntrophy between Pseudomonas aeruginosa and 2,3-butanediol fermenters within the context of optimized phenazine-based current generation in bioelectrochemical systems

过去，利用微生物反应进行生物技术应用主要限于纯培养。然而，在自然界中，微生物通常会协同行动，因为协同合作能够克服代谢和能量挑战。不幸的是，我们对特定微生物相互作用的了解仍然很少。生物电化学系统（BES）可以利用协同微生物将有机物厌氧转化（氧化）为二氧化碳和电流。因此，已经确定了具有特定代谢功能的关键微生物参与者，如有机物水解，发酵，氧化还原介体穿梭或直接胞外电子转移。成功应用BES的一个主要挑战是开发优化的微生物BES催化剂。实现这一目标的一个明确的途径是了解这些关键参与者如何相互作用，并设计社区来利用这些interactions.Previous工作已经表明，2，3-丁二醇发酵产气肠杆菌和电子介质生产者铜绿假单胞菌之间的重要协同电流生产。在该共培养物中，发酵罐将糖主要转化为2，3_丁二醇，其继而被铜绿假单胞菌吸收。铜绿假单胞菌使用2，3-丁二醇来产生增加量的毒力因子绿脓菌素，绿脓菌素是一种氧化还原介体，其能够增加BES阳极处的电流产生。这一提议力求从生态学和分子学角度理解这种协同作用，这种协同作用似乎是由发酵产物2，3-丁二醇介导的。此外，这两种生物（但也有铜绿假单胞菌与类似的发酵罐）在土壤环境中和肺部感染过程中相遇，使得这种协同作用的含义比仅仅BES应用广泛得多。在拟议的工作中，我们将对铜绿假单胞菌与各种2，3-丁二醇发酵罐之间的协同作用进行彻底的生态评估：我们将研究物种间的通信和生理反应的程度，在双方的合作伙伴和铜绿假单胞菌的群体感应和毒力因子的形成的影响，从而BES将被用来作为一个原位分析工具，以量化绿脓菌素。我们将进一步确定铜绿假单胞菌最佳协同行为的理想生理条件：BES中的发酵罐共培养，即我们将学习控制二元共培养。为了更全面地了解这种协同作用，我们将研究铜绿假单胞菌的相关生理过程，以回答以下问题：2，3-丁二醇是如何被感知的？如何影响群体感应调节网络？除了发出信号外，还有其他代谢作用吗？最后，我们将整合所有观察到的表型和生理结果的共培养协同作用的生理生态模型，这将作为未来的基础，更复杂的微生物网络在BES。

In the past, exploiting microbial reactions for biotechnological applications was mainly limited to pure cultures. In nature, however, microorganisms typically act in concert because synergistic collaborations are able to overcome metabolic and energetic challenges. Unfortunately, our knowledge on specific microbial interactions is still scarce. Bioelectrochemical systems (BESs) can utilize collaborative microorganisms for the anaerobic conversion (oxidation) of organic matter to carbon dioxide and electric current. Thereby, key microbial players with specific metabolic functions like organics hydrolysis, fermentation, redox mediator shuttling or direct extracellular electron transfer have already been identified. One major challenge for the successful application of BES is the development of optimized microbial BES catalysts. A clear path to achieve this goal is to understand how these key players interact together and to design communities to exploit these interactions.Previous work has shown an important synergistic current production between the 2,3-butanediol fermenter Enterobacter aerogenes and the electron-mediator producer Pseudomonas aeruginosa. In this co-culture, the fermenter digests sugars to mainly 2,3-butanediol, which in turn, is taken up by P. aeruginosa. P. aeruginosa uses 2,3-butanediol to produce increased amounts of the virulence factor pyocyanin, a redox mediator, which enables increased current production at a BES anode. This proposal strives for an ecological and molecular understanding of this synergistic interaction, which seems to be mediated by the fermentation product 2,3-butanediol. Further, these two organisms (but also P. aeruginosa with similar fermenters) encounter one another in soil environments and during lung infections, making implications of this synergism much broader than just BES applications.In the proposed work, we will conduct a thorough ecological evaluation of the synergism between P. aeruginosa and various 2,3-butanediol fermenters: we will study the extent of interspecies communication and physiological responses in both partners and the effect on P. aeruginosa quorum sensing and virulence factor formation, whereby BES will be used as an in-situ analytical tool to quantify pyocyanin. We will further determine ideal physiological conditions for optimum synergistic behavior of P. aeruginosa : fermenter co-cultures in BES, i.e. we will learn to control the binary co-culture. For a comprehensive understanding of the synergism, the related physiological processes in P. aeruginosa will be investigated to answer the following questions: How is 2,3-butanediol sensed?; How is the quorum sensing regulatory network influenced?; Is there a metabolic effect beyond just signaling? Finally, we will integrate all observed phenotypic and physiological results in an physio-ecological model of the co-culture synergism, which will serve as a foundation for future, more complex microbial networks in BES.