Three-dimensional biofilm model with individual cells and continuum EPS matrix
Three-dimensional biofilm model with individual cells and continuum EPS matrix
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DOI：
10.1002/bit.20917
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发表时间：
2006-08-05
影响因子：
3.8
通讯作者：
Heyden, Anders
中科院分区：
文献类型：
--
作者：
Alpkvist, Erik;Picioreanu, Cristian;Heyden, Anders
通过将微生物颗粒的个体描述与生物膜基质的连续表示相结合，得到了一种创新类型的生物膜模型。这种混合模型保留了每种方法的优点，同时在两个或三个空间维度上提供了对生物膜结构的时间发展的更真实的描述。一般模型推导考虑了任何可能数量的可溶组分。这些是底物和代谢产物，它们在单个微生物细胞内的生物膜中扩散和反应。细胞生长，分裂，并产生胞外聚合物（EPS）在多物种模型设置。EPS矩阵被描述为一个不可压缩的粘性流体，它可以膨胀和收缩，由于产生和消耗过程的连续表示。细胞移动是由于集落中细胞之间的推动机制和由EPS动力学支持的平流机制。细胞和EPS两者的脱离遵循连续体方法，而细胞以离散事件附着。两个案例研究模型说明。生物膜固结是由EPS和细胞降解过程引起的收缩来解释的。该机制描述了在营养限制条件下，在生物膜深度中形成更致密的细胞层和发生不规则形状的生物膜表面。通过在由异养细胞产生的EPS基质中自养微生物菌落的生长来研究微菌落形成。氨和亚硝酸盐氧化细菌（NOB）的菌落的大小和形状进行了比较研究，在一个标准的生物膜和从膜侧曝气的生物膜。(c)2006 Wiley Periodicals，Inc.
An innovative type of biofilm model is derived by combining an individual description of microbial particles with a continuum representation of the biofilm matrix. This hybrid model retains the advantages of each approach, while providing a more realistic description of the temporal development of biofilm structure in two or three spatial dimensions. The general model derivation takes into account any possible number of soluble components. These are substrates and metabolic products, which diffuse and react in the biofilm within individual microbial cells. The cells grow, divide, and produce extracellular polymeric substances (EPS) in a multispecies model setting. The EPS matrix is described by a continuum representation as incompressible viscous fluid, which can expand and retract due to generation and consumption processes. The cells move due to a pushing mechanism between cells in colonies and by an advective mechanism supported by the EPS dynamics. Detachment of both cells and EPS follows a continuum approach, whereas cells attach in discrete events. Two case studies are presented for model illustration. Biofilm consolidation is explained by shrinking due to EPS and cell degradation processes. This mechanism describes formation of a denser layer of cells in the biofilm depth and occurrence of an irregularly shaped biofilm surface under nutrient limiting conditions. Micro-colony formation is investigated by growth of autotrophic microbial colonies in an EPS matrix produced by heterotrophic cells. Size and shape of colonies of ammonia and nitrite-oxidizing bacteria (NOB) are comparatively studied in a standard biofilm and in biofilms aerated from a membrane side. (c) 2006 Wiley Periodicals, Inc.