Collaborative Research: ERASE-PFAS: Remediation of Per- and Polyfluoroalkyl Substances in Wastewater using Anaerobic Membrane Bioreactors​

全氟和多氟烷基物质（PFASs）用于许多消费品和工业产品。全氟辛烷磺酸已在家庭饮用水系统中发现，并已在全球范围内的生态系统中得到确认。全氟辛烷磺酸在环境中具有高度持久性，因此被称为“永远的化学物质”。“因为全氟辛烷磺酸对人类和野生动物有毒，所以找到有效的方法从供水中消除这些化学物质是很重要的。”本研究的目标是通过开发厌氧膜生物反应器（anmbr）来解决这一需求，该反应器依靠细菌和膜来去除和破坏水中的全氟烷烃。这一目标将通过一个多阶段的研究项目来实现，开发微生物培养物，利用新的分子生物学方法转化PFAS，表征PFAS治疗前后的转化过程，并利用最新的科学方法评估最终产品的反应性。这项研究的成功完成将使我们更好地了解细菌如何降解全氟辛烷磺酸，并确定降解如何影响这些产品的毒性。社会效益包括潜在的技术发展，以解决国家对低成本、有效的PFAS治疗的迫切需求。其他好处包括通过外联、招聘和培训提高科学素养和STEM多样性。全氟辛烷磺酸的广泛使用和极强的稳定性使得其在环境中无处不在。由于碳氟键的惰性，PFASs对生物降解的抗拒性知之甚少。然而，在还原条件下，还原性脱氟在热力学上是有利的，这是一个令人困惑的发现，值得使用新兴的化学和分子生物技术工具进一步探索。该项目通过对anmbr中PFASs生物降解的多阶段研究来解决这一需求。anmbr将厌氧处理与膜分离相结合，提供低能耗的生物处理。该项目的总体目标是开发一套工具，以更好地了解PFAS生物处理。为实现这一目标而设计的具体目标是：i)证明在anmbr中全氟磺酸的还原除氟作用，并使用乳剂、配对分离和串联（大规模）PCR识别除氟微生物种群，在细胞水平上将系统发育基因与除卤基因联系起来；ii)利用高分辨率液相色谱/质谱法和19F核磁共振波谱法表征生物转化产物并评估降解效率；iii)利用综合转录组学和代谢组学方法系统地评估PFAS混合物在哺乳动物细胞系中的生物活性。这项研究的成功完成具有强大的潜力，以改变我们对传统和新兴全氟磺酸水处理系统的认识。这些信息可以导致PFAS的有效生物处理替代方案，解决国家的关键需求。更广泛的科学和社会影响包括，如果在复杂的全氟磺酸钠混合物中建立协同相互作用的证据得到确立，目前建立全氟磺酸钠健康咨询的做法可能会发生范式转变。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Per- and polyfluoroalkyl substances (PFASs) are used in many consumer and industrial products. PFASs have been found in domestic drinking water systems and have been identified in ecosystems on a global basis. PFASs are highly persistent in the environment, and as such have been called ‘forever chemicals.’ Because PFASs are toxic to humans and wildlife, it is important to find efficient ways to eliminate these chemicals from water supplies. The goal of this research is to address this need through the development of anaerobic membrane bioreactors (AnMBRs) that rely on both bacteria and membranes to remove and destroy PFASs from water. This goal will be achieved through a multiphase research program to develop microbial cultures that transform PFAS using novel molecular biological approaches, characterize the PFAS transformation process before and after treatment, and assess the reactivity of end products using state-of-the-science approaches. Successful completion of this research will allow us to better understand how bacteria degrade PFASs and determine how degradation affects the toxicity of these products. Societal benefits include potential development of technology to address the urgent national need for low cost, effective PFAS treatment. Additional benefits include increasing scientific literacy and STEM diversity through outreach, recruitment, and training.The widespread use and extreme stability of PFASs have resulted in their ubiquitous occurrence in the environment. The recalcitrance of PFASs to biodegradation resulting from the inertness of carbon-fluorine bonds is poorly understood. However, reductive defluorination is thermodynamically favorable under reducing conditions, a puzzling finding that warrants further exploration using emerging chemical and molecular biotechnological tools. This project addresses this need through a multi-stage investigation of the biodegradation of PFASs in AnMBRs. AnMBRs combine anaerobic treatment with membrane separation, providing low-energy intensive biological treatment. The overall goal of this project is to develop a set of tools leading to a better understanding of PFAS biotreatment. The specific objectives designed to achieve this goal are to: i) demonstrate reductive defluorination of PFASs in AnMBRs and identify defluorinating microbial populations using emulsion, paired isolation, and concatenation (epic)PCR to link phylogenetic genes with dehalogenation genes at a cellular level; ii) characterize biotransformation products and assess degradation efficiency using high resolution liquid chromatography/mass spectrometry and 19F nuclear magnetic resonance spectroscopy; and iii) systematically evaluate biological activity of PFAS mixtures in mammalian cell lines using an integrated transcriptomics and metabolomics approach. Successful completion of this research holds strong potential to transform our knowledge of water treatment systems for legacy and emerging PFASs. Such information can lead to efficient biological treatment alternatives for PFAS, addressing a critical national need. Broader scientific and societal impacts include the potential for a paradigm shift in current practices for establishing PFAS health advisories should evidence of synergistic interactions in complex PFAS mixtures be established.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.