Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Langmuir. 2012 Jan 31;28(4):2262-8. doi: 10.1021/la2038262. Epub 2011 Dec 22.
Moringa oleifera (Moringa) seeds contain a natural cationic protein (MOCP) that can be used as an antimicrobial flocculant for water clarification. Currently, the main barrier to using Moringa seeds for producing potable water is that the seeds release other water-soluble proteins and organic matter, which increase the concentration of dissolved organic matter (DOM) in the water. The presence of this DOM supports the regrowth of pathogens in treated water, preventing its storage and later use. A new strategy has been established for retaining the MOCP protein and its ability to clarify and disinfect water while removing the excess organic matter. The MOCP is first adsorbed and immobilized onto sand granules, followed by a rinsing step wherein the excess organic matter is removed, thereby preventing later growth of bacteria in the purified water. Our hypotheses are that the protein remains adsorbed onto the sand after the functionalization treatment, and that the ability of the antimicrobial functionalized sand (f-sand) to clarify turbidity and kill bacteria, as MOCP does in bulk solution, is maintained. The data support these hypotheses, indicating that the f-sand removes silica microspheres and pathogens from water, renders adhered Escherichia coli bacteria nonviable, and reduces turbidity of a kaolin suspension. The antimicrobial properties of f-sand were assessed using fluorescent (live-dead) staining of bacteria on the surface of the f-sand. The DOM that can contribute to bacterial regrowth was shown to be significantly reduced in solution, by measuring biochemical oxygen demand (BOD). Overall, these results open the possibility that immobilization of the MOCP protein onto sand can provide a simple, locally sustainable process for producing storable drinking water.
辣木（Moringa）种子含有一种天然阳离子蛋白（MOCP），可用作水澄清的抗菌絮凝剂。目前，使用辣木种子生产饮用水的主要障碍是种子会释放出其他水溶性蛋白质和有机物，从而增加水中溶解有机物（DOM）的浓度。这种 DOM 的存在支持了处理水中病原体的再生，从而阻止了其储存和以后的使用。已经建立了一种新的策略，用于保留 MOCP 蛋白及其澄清和消毒水的能力，同时去除多余的有机物。首先将 MOCP 吸附并固定在砂粒上，然后进行冲洗步骤，去除多余的有机物，从而防止纯化水中的细菌以后生长。我们的假设是，在功能化处理后，蛋白质仍会吸附在沙子上，并且抗菌功能化砂（f-sand）的能力保持不变，即像在大量溶液中那样，澄清浊度并杀死细菌。数据支持这些假设，表明 f-sand 从水中去除了硅微球和病原体，使附着的大肠杆菌细菌失去活性，并降低了高岭土悬浮液的浊度。通过对 f-sand 表面的细菌进行荧光（死活）染色来评估 f-sand 的抗菌性能。通过测量生化需氧量（BOD），表明溶液中可以促进细菌再生的 DOM 显著减少。总的来说，这些结果表明，将 MOCP 蛋白固定在沙子上可能为生产可储存饮用水提供一种简单、本地可持续的方法。
