Structure function relationship of electroactive biofilms in microbial fuel and electrolysis cells

该提案旨在确定允许在阳极反应中开发和应用优化的电活性生物膜的通用工艺和设计规则。因此，我们将研究生物电化学系统中表面化学、生物膜形成和结构以及电流产生之间的关系。此外，还将研究电子穿梭对阳极生物膜的发育和活性以及它们的长期稳定性的影响。这些电活性生物膜中的微生物将电极作为呼吸链的末端电子受体的能力，可用于废水处理厂可持续去除有机碳或用于阳极辅助发酵。这两个系统的有效性取决于可实现的电流密度。然而，关于电极材料及其表面化学对电活性生物膜形成的影响，目前还缺乏基础性的知识。此外，我们不知道有效的电活性生物膜的结构，也不知道在这些生物膜中整合可持续的电子穿梭是否可以在更长的时间内产生更高的电流密度。我们建议，有可能确定、研究和定义适用于广泛应用的高效阳极基工艺的一般设计规则。因此，我们将努力了解阳极工艺的局限性，并制定阳极生物膜演变的设计规则。Stom教授和他的研究小组(俄罗斯)将研究表面化学、表面活性剂、亲水性和疏水性程度、电极极化和电场对阳极生物膜形成的动力学、稳定性和生理学的影响。Gescher教授(德国)的小组将开发将介体分子整合到生物膜基质中的方法，以便通过更厚的活性生物膜获得更高的电流密度。此外，该小组还将研究阳极生物膜催化剂的长期活性以及工艺异质性的原因。这两项任务都将根据目前的生产情况以及通过评估生物膜不同区域的生物活性来进行评估。结果将在两组中合并，并将通过在废水处理系统(Stom教授的小组)以及阳极发酵过程(Gescher教授的小组)中的应用进行评估。与对照生物膜相比，将使用缺氧荧光标记、转录组和元基因组分析以及碳消除速率和代谢物产物的形成来评估生物膜的长期稳定性和功能活性。最后，基于前28个月取得的成果，两个研究小组将共同设计一个可扩展的反应堆，以研究开发的设计规则在真实(ISTIC)条件下的适用性。

This proposal aims at identifying generic process and design rules that allow for the development and application of optimized electroactive biofilms in anode reactions. Hence, we will study the correlation between surface chemistry, biofilm formation and architecture as well as current production in bioelectrochemical systems. Moreover, the effect of electron shuttles on the development and activity of anode biofilms as well as their long-term stability will be studied. The ability of microbes in these electroactive biofilms to use electrodes as the terminal electron acceptor of their respiratory chain can be used in wastewater treatment plants for the sustainable removal of organic carbon or in anode-assisted fermentations. The effectiveness of both systems depends on the achievable current density. However, there is still a lack of fundamental knowledge regarding the effect of electrode-materials and their surface chemistry on electroactive biofilm formation. Moreover, we do not know the architecture of an efficient electroactive biofilm and whether the integration of sustainable electron shuttles in these biofilms can lead to higher current densities over longer periods of time. We suggest that it is possible to identify, study and define general design rules for efficient anode-based processes that are congruent to a wide range of applications. Therefore, we will strive to understand the limitations of anode-based processes and formulate design rules for the evolution of anode biofilms.Professor Stom and his research group (Russia) will study the effects of surface chemistry, surfactants, the degree of hydrophilicity and hydrophobicity, polarization of electrodes and electric field on the kinetics, stability and physiology of biofilm formation on the anode electrodes. The group of Professor Gescher (Germany) will develop methods for integrating mediator molecules into a biofilm matrix in order to obtain higher current densities through thicker active biofilms. Moreover, the group will study the long-term activity of anodic biofilm-catalysts and reasons for process heterogeneities. Both tasks will be evaluated in terms of current production, as well as in by assessing biological activity in various areas of the biofilm. The results will be combined in both groups and will be evaluated by application in wastewater treatment systems (Professor Stom's group), as well as in anode fermentation processes (Professor Gescher's group). Compared to control biofilms, long-term stability and functional activity will be evaluated using anoxic fluorescent markers, transcriptomic and metagenomic analysis, as well as, by the rate of elimination of carbon and the formation of metabolites products. Finally, based on the results achieved during the first 28 months, both research groups will jointly design a scalable reactor to study the applicability of the developed design rules under real(istic) conditions.