†Department of Environmental Microbiology, UFZ - Helmholtz Centre for Environmental Research, Permoserstrasse 15, 04318 Leipzig, Saxony, Germany.
‡Department of Civil and Environmental Engineering, 3-133 Markin/CNRL Natural Resources Engineering Facility, University of Alberta, Edmonton, Alberta T6G 2W2, Canada.
Environ Sci Technol. 2015 May 5;49(9):5663-71. doi: 10.1021/es506245y. Epub 2015 Apr 16.
Microbial biofilms can cause severe problems in technical installations where they may give rise to microbially influenced corrosion and clogging of filters and membranes or even threaten human health, e.g. when they infest water treatment processes. There is, hence, high interest in methods to prevent microbial adhesion as the initial step of biofilm formation. In environmental technology it might be desired to enhance bacterial transport through porous matrices. This motivated us to test the hypothesis that the attractive interaction energy allowing cells to adhere can be counteracted and overcome by the shear force induced by electroosmotic flow (EOF, i.e. the water flow over surfaces exposed to a weak direct current (DC) electric field). Applying EOF of varying strengths we quantified the deposition of Pseudomonas fluorescens Lp6a in columns containing glass collectors and on a quartz crystal microbalance. We found that the presence of DC reduced the efficiency of initial adhesion and bacterial surface coverage by >85%. A model is presented which quantitatively explains the reduction of bacterial adhesion based on the extended Derjaguin, Landau, Verwey, and Overbeek (XDLVO) theory of colloid stability and the EOF-induced shear forces acting on a bacterium. We propose that DC fields may be used to electrokinetically regulate the interaction of bacteria with surfaces in order to delay initial adhesion and biofilm formation in technical installations or to enhance bacterial transport in environmental matrices.
微生物生物膜会在技术设备中引起严重问题，它们可能导致微生物影响的腐蚀和过滤器及膜的堵塞，甚至威胁人类健康，例如当它们污染水处理过程时。因此，人们非常关注防止微生物附着的方法，因为这是生物膜形成的初始步骤。在环境技术中，可能希望增强细菌通过多孔基质的传输。这促使我们检验这样一个假设，即允许细胞附着的吸引力相互作用能被电渗流（EOF，即在暴露于弱直流电（DC）电场的表面上的水流）产生的剪切力抵消和克服。我们应用不同强度的 EOF 来量化假单胞菌荧光 Lp6a 在含有玻璃收集器的柱子和石英晶体微天平上的沉积。我们发现，直流的存在降低了初始附着和细菌表面覆盖率的效率，超过 85%。提出了一个模型，该模型基于胶体稳定性的扩展 Derjaguin、Landau、Verwey 和 Overbeek（XDLVO）理论以及作用于细菌的 EOF 诱导剪切力，定量解释了细菌附着减少的原因。我们提出，直流场可用于电动调节细菌与表面的相互作用，以延缓技术设备中的初始附着和生物膜形成，或增强环境基质中的细菌传输。
