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

1605177 Nerenberg在环境技术和工艺中，细菌生物膜被认为起着重要作用。然而，人们对它们是如何形成的、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的了解却很少。为了更好地了解细菌生物膜，本研究将表征生物膜的机械性能，特别是与GE Power and Water的ZeeLung膜曝气生物膜反应器相关的逆扩散生物膜，以预测生物膜的变形和分离。生物膜变形和分离仍然是一个黑匣子，没有可靠的机械方法来预测它们。此外，很少有研究人员考虑生物膜的粘弹性行为。本研究将探讨异养生物膜、硝化生物膜及异养与硝化复合生物膜的黏弹性特性。它使用独特的原位微尺度技术来评估机械性能的空间分布。除了研究纯培养生物膜，这项研究将是第一个解决共培养生物膜的机械性能，其中已知的硝化菌和异养菌共存。纯培养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在原位确定并与机械性能相关。将评估作为时间和剪切应力的函数的性质，并且还将评估胞外聚合物物质破坏剂对机械性质的影响。这是第一个研究，以解决与环境系统相关的生物膜的微尺度空间变异性。它还将解决一种特殊类型的管状鞘结构中观察到的异养，反扩散生物膜，导致致密，凝胶状生物膜。这项研究将开发新的信息的空间和时间变化的机械性能在生物膜在几个环境相关的条件下，并将这些属性与胞外聚合物的特性。它还将使用一种新的相场模型来预测变形和拆离，以及空间非均匀性的影响。该项目将培养一名博士生，几名本科生研究人员和本科生的研究经验，并部分支持一名博士后研究人员。它将为格拉德生或博士后提供GE的现场体验。Notre Dame和GE之间的研讨会将在一家全球膜工艺公司传播生物膜研究和工艺开发方面的知识，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.