A Novel Biomechanical Model of Bacterial Adhesion and Aggregation

该奖项的研究目标是建立一个基本的生物力学模型，能够预测和提高水过滤和生物修复的效率。具体做法如下。能源部鉴定的微生物菌株将在离子浓度与受污染水道相匹配的水环境中培养。使用原子力显微镜进行微观表征将确定单细胞的表面电位、界面作用力、粘附能和弹性模量、表面粗糙度和砂粒的Zeta电位等。使用标准填充柱测试进行宏观表征将测量不同水流量和温度下的过滤效率。这些信息将被输入到细胞黏附-分离、液-固相互作用和细胞在沙子基质上的统计保留的新模型中。基于快速的单细胞特性，最终可以预测和测试无数细菌菌株的宏观过滤行为。如果成功，这项研究的好处将包括：(I)预测微生物在多孔介质中的去向和迁移行为；(Ii)原位或强化地下生物修复和生物强化的设计、评估和可行性研究；(Iii)有效实施工程(砂滤池)或自然(银行过滤)过滤工艺用于水处理；(Iv)饮用水供应中病原体的迁移和微生物强化采油。从长远来看，随着世界人口的增长和全球气候的剧烈变化，这些研究成果将有助于解决21世纪对清洁饮用水日益增长的需求。

The research objective of this award is to derive a fundamental biomechanical model capable of predicting and improving efficiency of water filtration and bioremediation. The approach is as follows. Microbial strains identified by the Department of Energy will be cultured in aqueous environment with ionic concentration matching that of the polluted waterways. Micro-characterization using atomic force microscopy will determine surface potential, intersurface forces, adhesion energy, and elastic modulus of single cells, surface roughness and zeta potential of sand grains etc. Macro-characterization using standard packed column tests will measure filtration efficiency for different water flow rates and temperature. Such information will be fed into a new model of adhesion-detachment of cells, liquid-solid interaction, and statistical retention of cells on sand substrates. Based on quick single cell characterization, macroscopic filtration behavior of a myriad of bacterial strains can ultimately be predicted and tested. If successful, the benefits of this research will include (i) prediction of fate and transport behavior of microorganisms in porous media, (ii) design, evaluation and feasibility studies of in-situ or enhanced subsurface bioremediation and bioaugmentation, (iii) effective implementation of engineered (sand filters) or natural (bank filtration) filtrations processes for water treatments, (iv) migration of pathogens in drinking water supplies and microbial enhanced oil recovery. The research results will in a long run contribute to resolving the increasing need for clean drinking water in the 21st century with growing world population and drastic global climate change.