GOALI: Predicting Biofilm Deformation and Detachment Using In-Situ Micro-Rheology and Phase-Field Modeling

[1605177]细菌生物膜在环境技术和工艺中发挥着重要作用。然而，对于它们是如何形成的，它们的机械强度，以及在许多情况下，它们对环境中观察到的实际变化的贡献，人们知之甚少。为了更好地了解细菌生物膜，本研究将对生物膜的力学特性进行表征，特别是与GE Power and Water的ZeeLung膜曝气生物膜反应器相关的反扩散生物膜，以便预测生物膜的变形和脱离。生物膜的变形和脱离仍然是一个黑盒子，没有可靠和机械的方法来预测它们。此外，很少有研究人员考虑到生物膜的粘弹性行为。本研究将确定异养、硝化和异养和硝化联合生物膜的力学性能，考虑它们的粘弹性行为。它使用一种独特的原位微尺度技术来评估力学性能的空间分布。除了研究纯培养生物膜外，这项研究将首次解决共培养生物膜的机械特性，其中已知的硝化菌和异养菌共存。纯和共培养的结果将与GE的环境生物膜进行比较。细胞外聚合物基质的组成将被原位测定，并与力学性能有关。性能将被评估为时间和剪切应力的函数，也将评估细胞外聚合物物质干扰物对机械性能的影响。这是首次研究与环境系统相关的生物膜的微尺度空间变异性。它还将讨论在异养反扩散生物膜中观察到的一种特殊类型的管状鞘结构，这种结构导致致密的凝胶状生物膜。该研究将为几种环境相关条件下生物膜力学特性的时空变化提供新的信息，并将这些特性与细胞外聚合物特性联系起来。它还将使用一种新的相场模型来预测变形和脱离，以及空间异质性的影响。本项目将培养1名博士生、数名本科生科研人员和本科生科研经验，部分支持1名博士后科研人员。它将为研究生或博士后提供在通用电气的现场体验。巴黎圣母院大学和通用电气公司之间的研讨会将在全球膜工艺公司传播生物膜研究和工艺开发知识，并促进当地劳动力的发展。

1605177NerenbergIt is recognized in environmental technology and processes that bacterial biofilms play an important role. However, the understanding of how they are formed, their mechanical strength, and, in many cases, their contribution to actual changes which are observed in the environment, are poorly understood. To gain a better understanding of bacterial biofilms, this research will characterize the mechanical properties of biofilms, especially counter-diffusional biofilms relevant to the ZeeLung Membrane Aerated Biofilm Reactor from GE Power and Water, to allow prediction of biofilm deformation and detachment.Biofilm deformation and detachment remains a black box, where there are no reliable and mechanistic means to predict them. Also, few researchers have considered the viscoelastic behavior of biofilms. This research will determine the mechanical properties of heterotrophic, nitrifying, and combined heterotrophic and nitrifying biofilms, considering their viscoelastic behavior. It uses a unique, in-situ micro-scale technique to assess the spatial distribution of mechanical properties. In addition to studying pure-culture biofilms, this study will be the first to address the mechanical properties of a co-culture biofilm, where a known nitrifier and heterotrophs co-exist. The pure and co-culture results will be compared with an environmental biofilm at GE. The composition of the extracellular polymeric substance matrix will be determined in-situ and related to mechanical properties. The properties will be assessed as a function of time and shear stress, and also will assess the effect of an extracellular polymeric substance disruptor on mechanical properties. This is the first research to address the micro-scale spatial variability of biofilms relevant to environmental systems. It will also address a special type of tubular, sheath structure observed in heterotrophic, counter-diffusional biofilms, leading to dense, gelatinous biofilms. The research will develop novel information on the spatial and temporal variation of mechanical properties in biofilms under several environmentally relevant conditions, and will relate these properties to extracellular polymeric substance characteristics. It also will use a novel phase-field model to predict deformation and detachment, and the impact of spatial heterogeneity. The project will train one doctoral student, several undergraduate researchers and research experiences for undergraduate students, and partially support a post-doctoral researcher. It will provide an on-site experience at GE for a grad student or post-doc. Workshops between Notre Dame and GE will disseminate knowledge on biofilm research and process development at a global membrane process company, and promote local workforce development.