GOALI: A New Strategy for Biofouling Control of Water Filtration Membranes Using D-amino Acids

尽管在过去的几十年里对生物膜技术进行了大量的研究，但生物污垢仍然是膜技术在水处理中应用的最大障碍。最近发现细菌通常产生的D-氨基酸(D-AAs)可以在非常低的浓度下引发生物膜的分解，受此启发，研究人员提出了一个大学和行业合作项目，以开发一种新的、高效和环境友好的方法来控制使用D-AAs的膜系统的生物污染。拟议研究的主要目标是评估D-AA在废水处理膜系统中控制生物污染的潜力并制定策略。他们的中心假设是，D-AA是不同细菌用来介导生物膜分解的常见跨物种信号化合物；仔细操纵这一调节过程可以防止生物膜的形成并清除预先形成的生物膜。我们合作的长期目标是开发一种高效、环保的膜清洗方法并将其商业化，用于膜生物反应器(MBR)和反渗透(RO)系统中的生物污染控制。他们将首先对所有19种D-AA进行单独和组合筛选，以确定它们对模拟细菌单一培养物以及来自传统活性污泥和MBR的混合培养物的生物膜形成和分解的单独和协同作用。他们将通过探索细菌对D-氨基酸在细胞生长、肽聚糖合成、表面蛋白和脂多糖的反应中的反应，并将它们与细胞与细胞和细胞表面的黏附以及生物膜结构的完整性联系起来，利用具有良好特性的杆菌模型来研究所涉及的关键机制。还将调查细菌在长期暴露期间产生抗药性的可能性，并评估相应的缓解策略。从这些基础研究中获得的信息将被用于开发实用的生物污染控制策略，这些策略将在实验室膜单元、小规模MBR-RO系统和中试MBR系统中进行测试。这将确定细菌的共性？S使用D-氨基酸作为生物膜调节的物种间信号，并在细胞水平上提供对这一过程的机械理解。这不仅将促进我们对生物膜形成和调控的了解，而且也为利用这一特定信号途径开发生物污染控制策略打开了一扇机会之窗。这是首次对所有19种D-氨基酸进行系统研究，第一次评估了DAA对多物种生物膜的影响，第一次研究了D-AA诱导的细胞生理变化与生物膜形成/分解的关系，第一次寻求这一新科学的工程应用。行业参与使得在实际条件下和中试规模测试生物污染控制方法成为可能，促进了科学研究的工业应用。从根本上讲，该项目有助于我们了解细菌调节生物膜的化学信号途径，这对微生物学、生物化学、环境、生物医学和化学工程等许多科学领域都有重大影响。从应用的角度来看，基于D-AA或D-AA类似物的生物膜控制策略可用于大量的环境、生物医学和工业系统，如传感器、医疗植入物、水/废水处理和分配系统、冷却塔和食品加工设备，以防止生物膜的有害影响。大学和产业界的合作提供了从基础研究到技术开发和实施的迫切需要的桥梁。拟议的教育和研究活动将通过新的实验单元和客座讲座来丰富我们的本科生和研究生课程，并为研究生和本科生提供研究培训，特别是在招收女性和少数民族学生方面。学生将参与工业研发，将最先进的学术研究直接应用于工业技术开发，在实际工程系统上与实践者密切合作，并学习跨学科的有效沟通。PI和行业合作PI还将联合为高中教师和环境工程师提供教育经验。

PI: Qilin LiProposal Number: 1134427Biofouling remains the biggest barrier to application of membrane technology in water and wastewater treatment despite intensive research in the past decades. Inspired by the recent discovery that D-amino acids (D-AAs) commonly produced by bacteria can trigger bioiflm disassembly at very low concentrations, the researchers propose a university-industry collaborative project to develop a novel, highly effective and environmentally friendly approach to biofouling control in membrane systems using D-AAs. The main objective of the proposed research is to assess the potential of and develop strategies for using D-AAs to control biofouling in wastewater treatment membrane systems. Their central hypothesis is that D-AAs are common interspecies signal compounds used by different bacteria to mediate biofilm disassembly; careful manipulation of this regulation process can prevent biofilmformation and remove preformed biofilms. The long term goal of our collaboration is to develop and commercialize a highly effective, environmentally benign membrane cleaning method for biofouling control in membrane bioreactors (MBR) and reverse osmosis (RO) systems. They will first screen all 19 D-AAs individually and in combinations for their individual and synergistic effects on biofilm-formation and disassembly of model bacterial single cultures as well as mixed cultures from conventional activated sludge and MBR. Using well characterized model bactedria, they will investigate the key mechanisms involved by probing bacterial responses to D-AAs in cell growth, peptidoglycan synthesis, surface proteins and lipopolysaccharides, and relating them to cell-cell and cellsurface adhesion as well as biofilm structural integrity. The potential of bacteria developing resistance over long term exposure will also be investigated and corresponding mitigation strategies evaluated. Information obtained from these fundamental researches will be used to develop practical biofouling control strategies, which will be tested in laboratory membrane units, a small scale MBR-RO system, and a pilot MBR system.The proposed study explores a new paradigm of membrane biofouling control based on a recent scientific discovery. It will determine the commonality in bacteria?s use of D-AAs as interspecies signals for biofilm mediation and provide a mechanistic understanding of the process at the cellular level. This will not only advance our knowledge in biofilm formation and regulation, but also open a window of opportunity for developing biofouling control strategies utilizing this specific signal pathway. It is the first study to systematically examine all 19 D-AAs, the first to assess the impact of DAAs on multi-species biofilms, the first to investigate the connection between D-AA induced cell physiological changes and biofilms formation/ disassembly, and the first to seek engineering application of this new science. Industry participation makes it possible to test the biofouling control methods using realistic conditions and at pilot scale, facilitating industry application of the scientific research.From the fundamental aspect, the project contributes to our understanding of chemicalsignal pathways used by bacteria to regulate biofilms, which has great impact on many scientific fields including microbiology, biochemistry, environmental, biomedical, and chemical engineering. From the application point of view, D-AA or D-AA analogue based biofilm control strategies could be used in a large number of environmental, biomedical and industrial systems, e.g., sensors, medical implants, water/wastewater treatment and distribution systems, cooling towers and food processing equipment, to prevent detrimental impact of biofilms. The university-industry collaboration provides a much needed bridge from fundamental research to technology development and implementation. The education and research activities proposed will enrich our undergraduate and graduate curricula through a new lab module and guest lectures, and provide research training to graduate and undergraduate students with special effort in recruiting women and minority students. Students will be involved in industry R&D to take the state-of-the-art academic research directly to industrial technology development, work closely with practitioners on real engineering systems, and learn effective communication across disciplines. The PI and the industry co-PI will also jointly provide educational experiences to high school teachers and environmental engineers.