Collaborative Research: Microbial Flocculation Dynamics

研究者和他的同事们研究了水中多细胞微生物群落的种群动态。从实验室到海洋，这些群落无处不在，本研究的目的是促进对微生物絮凝的理解，微生物絮凝是微生物在悬浮中分裂和聚集的增殖过程。具体来说，研究人员使用半群、分形、偏微分方程和计算分析来推进一类新的结构化人口模型的理论和应用。模型开发、分析和实验验证之间的紧密耦合使我们能够深入了解这种全球普遍存在的微生物基本状态的生物力学和代谢适应。研究者和他的同事们被三个激励问题所引导：1)驱动絮体破碎的主要机制是什么？2)群落结构变异性如何影响种群增殖？3)为什么一些絮团种群分布趋近于自相似，而另一些则衰减为单分散？深入了解主要的微尺度机制可以极大地改变微生物种群的建模和控制。悬浮在液体中的微生物通常不是以单细胞的形式生活——通过碰撞和分离，它们在一个称为絮凝的过程中结合和重新组合。从实验室到海洋，这些微生物群落无处不在，它们的絮凝趋势对人类生活有着惊人的影响。例如，基于细胞培养的工业生物技术（例如，作为药物的蛋白质制造商）严重依赖于对微生物群落物理特性的预测。细菌群被用于全国各地的城市污水处理厂，作为清洁人类和工业废水的环境可持续部分。此外，流体中的细菌和藻类群落是生物塑料、生物燃料和沼气工业的重要组成部分。在自然环境中，藻类的絮凝特性在藻华中起着重要作用（从而对经济和健康产生负面影响）。研究者和他的同事开发和研究絮凝的数学模型，并进行实验来验证对簇大小分布和生长速度的预测。该项目旨在将对微生物絮凝的科学理解从基于简化的、理想化的絮凝模型转变为基于微观尺度的机制和代谢第一原理。我们对这些微生物群体行为的理解的进步可能会导致诸如生物燃料生产效率、废水处理的可持续手段和海洋藻华管理等各种社会挑战的显著改善。

The investigator and his colleagues study the population dynamics of aqueous, multi-cellular, microbial communities. These communities are ubiquitous from the laboratory to the ocean, and the objective of this research is to advance understanding of microbial flocculation, the process whereby proliferating clusters of organisms in suspension fragment and aggregate. Specifically, the researchers use semigroup, fractal, partial differential equation, and computational analysis to advance the theory and applications for a novel class of structured population models. The close coupling between the model development, analysis, and experimental validation allows insight into the biomechanical and metabolic adaptations of this globally pervasive and fundamental state of microbial existence. The investigator and his colleagues are guided by three motivating questions: 1) what are the dominant mechanisms driving floc fragmentation? 2) How does floc structure variability impact population proliferation? and 3) Why do some floc population distributions converge to self-similarity and others decay to mono-dispersion? Insight into the dominant microscale mechanisms could dramatically change both modeling and consequently control of microbial populations.Micro-organisms suspended in a fluid often do not live as single cells - by collision and separation they combine and recombine in a process called flocculation. These microbial communities exist everywhere from the laboratory to the ocean and the tendency to flocculate has a surprising impact on human life. For example, industrial biotechnologies based on cell cultures (e.g., in the manufacturer of proteins as drugs) rely heavily on predictions of the physical properties of microbial communities. Bacterial clusters are used in municipal sewage treatment plants across the country as an environmentally sustainable part of cleaning human and industrial wastewater. Moreover, bacterial and algal communities in a fluid are an essential part of the bioplastic, biofuel, and biogas industries. In natural settings, the flocculation properties of algae play an important role in algal blooms (and thus in the resultant negative economic and health impacts). The investigator and his colleagues develop and study mathematical models of flocculation and perform experiments to validate predictions of the distribution of cluster sizes and growth rates. This project aims to transform scientific understanding of microbial flocculation from one based upon simplified, idealized models of clusters to one based on microscale mechanistic and metabolic first principles. Advances in our understanding of the population behavior of these microbial aggregates could lead to dramatic improvements in such diverse societal challenges as biofuel production efficiency, sustainable means of handling wastewater, and management of oceanic algal blooms.