Abstract:
Imaging and modeling are two major approaches in biofilm research to understand the physical and biochemical processes involved in biofilm development. However, they are often used separately. In this study we combined these two approaches to investigate substrate mass transfer and mass flux. Cross-sectional biofilm images were acquired by means of optical coherence tomography (OCT) for biofilms grown on carriers. A 2D biofilm model was developed incorporating OCT images as well as a simplified biofilm geometry serving as structural templates. The model incorporated fluid flow, substrate transfer and biochemical conversion of substrates and simulated the hydrodynamics surrounding the biofilm structure as well as the substrate distribution. The method allowed detailed analysis of the hydrodynamics and mass transfer characteristics at the micro-scale. Biofilm activity with respect to substrate fluxes was compared among different combinations of flow, substrate availability and biomass density. The combined approach revealed that higher substrate fluxes at heterogeneous biofilm surface under two conditions: pure diffusion and when high flow velocity along the biofilms surface renders the whole liquid-biofilm interface to be highly active. In-between the two conditions the substrate fluxes across the surface of smooth biofilm geometry were higher than that of the heterogeneous biofilms.
摘要:
成像和建模是生物膜研究中的两种主要方法,以了解生物膜发育中涉及的物理和生化过程。然而,它们通常单独使用。在这项研究中,我们结合了这两种方法来研究底物传质和质量通量。通过光学相干断层扫描(OCT)获取在载体上生长的生物膜的横截面生物膜图像。开发了结合OCT图像以及用作结构模板的简化生物膜几何形状的2D生物膜模型。该模型结合了流体流动,底物的转移和生化转化,并模拟了生物膜结构周围的流体动力学以及底物的分布。该方法可以在微观尺度上详细分析流体动力学和传质特性。在不同的流动组合中比较了相对于底物通量的生物膜活性,基质可用性和生物量密度。组合方法表明,在两种条件下,异质生物膜表面的底物通量较高:纯扩散和沿生物膜表面的高流速使整个液体-生物膜界面具有高度活性。在这两种条件之间,光滑生物膜几何形状表面上的底物通量高于异质生物膜。