Department of Civil Engineering, MSC01 1070, University of New Mexico, Albuquerque, New Mexico 87131-0001, USA.
Environ Sci Technol. 2011 Feb 1;45(3):1055-60. doi: 10.1021/es101389u. Epub 2010 Dec 28.
Biofilm-based systems, including integrated fixed-film activated sludge and moving bed bioreactors, are becoming increasingly popular for wastewater treatment, often with the goal of improving nitrification through the enrichment of ammonia and nitrite oxidizing bacteria. We have previously demonstrated the utility of self-assembled monolayers (SAMs) as tools for studying the initial attachment of bacteria to substrata systematically varying in physicochemical properties. In this work, we expanded these studies to bacteria of importance in wastewater treatment systems and we demonstrated attachment rates were better correlated with surface energy than with wettability (water contact angle). Toward the long-term goal of improving wastewater treatment performance through the strategic design of attachment substrata, the attachment rates of two autotrophic ammonia-oxidizing bacteria (Nitrosomonas europaea and Nitrosospira multiformis) and a heterotroph (Escherichia coli) were evaluated using SAMs with a range of wettabilities, surface energies, and functional properties (methyl, hydroxyl, carboxyl, trimethylamine, and amine terminated). Cell attachment rates were somewhat correlated with the water contact angles of the SAMs with polar terminal groups (hydroxyl, carboxyl, trimethylamine, and amine). Including all SAM surfaces, a better correlation was found for all bacteria between attachment rates and surface free energy, as determined using the Lewis Acid-Base approach. The ammonia-oxidizers had higher adhesion rates on the SAMs with higher surface energies than did the heterotroph. This work demonstrated the successful application of SAMs to determine the attachment surface preferences of bacteria important to wastewater treatment, and it provides guidance for a new area of research aimed at improving treatment performance through rational attachment surface design.
基于生物膜的系统，包括一体化固定膜活性污泥和移动床生物反应器，在废水处理中越来越受欢迎，通常旨在通过富集氨氧化菌和亚硝酸盐氧化菌来改善硝化作用。我们之前已经证明了自组装单分子层 (SAM) 作为研究细菌在物理化学性质系统变化的基底上初始附着的工具的有效性。在这项工作中，我们将这些研究扩展到了对废水处理系统中重要的细菌，并证明了附着率与表面能的相关性优于与润湿性（水接触角）的相关性。为了通过有策略地设计附着基底来提高废水处理性能的长期目标，使用具有不同润湿性、表面能和功能特性（甲基、羟基、羧基、三甲胺和胺基）的 SAM 评估了两种自养氨氧化细菌（Nitrosomonas europaea 和 Nitrosospira multiformis）和一种异养菌（Escherichia coli）的附着率。细胞附着率与具有极性末端基团（羟基、羧基、三甲胺和胺基）的 SAM 的水接触角有些相关。包括所有 SAM 表面，所有细菌的附着率与通过路易斯酸碱方法确定的表面自由能之间都存在更好的相关性。氨氧化菌在表面能较高的 SAM 上的粘附率高于异养菌。这项工作证明了 SAM 成功地应用于确定对废水处理很重要的细菌的附着表面偏好，并且为旨在通过合理的附着表面设计来提高处理性能的新研究领域提供了指导。
