Arresting methanogenesis with bioelectrochemically generated hydrogen peroxide for producing volatile fatty acids

厌氧消化（AD）是一种很有前途和用途广泛的环境生物技术平台，可以将有机废物转化为富含能量的沼气，用于加热、发电和升级生产可再生天然气。AD还显示出将有机废物转化为挥发性脂肪酸（VFAs）的巨大潜力，挥发性脂肪酸可以作为制造高价值产品的基石。在有机废物的厌氧消化过程中，产乙细菌产生VFAs， VFAs也作为产甲烷细菌生产沼气的中间化合物。因此，抑制产甲烷菌已成为一种有前途的策略，以提高VFAs的生产，同时最大限度地减少有机废物厌氧消化过程中沼气的产生。本项目的总体目标是研究利用有机废物的生物电化学（BEC）转化产生的过氧化氢来抑制厌氧消化池中产甲烷细菌的生长和活性。为了实现这一目标，首席研究员建议探索一种集成的高效ad - bec膜分离系统的设计、评估和验证，该系统可以将有机废物转化为VFAs，并具有高产品收率和高纯度。这个项目的成功完成将通过产生基础知识来促进有机废物转化为高价值产品的可持续发展，从而造福社会。通过外联和教育活动，包括指导圣路易斯华盛顿大学的一名研究生和两名本科生，将为社会带来额外的好处。厌氧消化（AD）通过将有机废物转化为挥发性脂肪酸（VFAs）等高价值化学品，显示出对化学工业脱碳的巨大潜力，挥发性脂肪酸可以作为制造工业相关产品的基础材料。然而，调节和控制厌氧消化器的产物谱以最大限度地提高VFAs的产量和纯度的能力仍然是一个关键和未解决的挑战。该项目的目标是探索一种创新的方法，以最大限度地提高有机废物厌氧消化过程中VFA的产量和纯度。为了推进这一目标，首席研究员（PI）提出探索利用原位生成的过氧化氢来抑制产甲烷细菌的生长和活性，这些细菌利用VFAs作为中间化合物在厌氧沼气池中产生沼气。提议的甲烷生成抑制将在一个集成的VFA生产系统中进行研究，该系统包括一个用于产品生成的厌氧消化器，一个用于产品纯化/浓缩的膜分离模块，以及一个用于利用有机废物原位生成H2O2的生物电化学反应器。本研究的具体目标是：(1)通过综合实验和模型研究，进一步了解AD过程中H2O2抑制甲烷生成的机制；(2)评估热或电驱动膜系统对AD过程中产生的VFAs的有效分离和纯化；(3)探索建立一个可转换的规模系统，作为对拟议的集成VFA生产系统进行技术经济评估的平台。这项研究的成功完成有可能产生变革性影响，产生新的基础知识，推动开发和实施更有效和更具成本效益的技术，从有机废物中回收有价值的化学品和化合物。为了实施该项目的教育和推广活动，项目计划将这项研究的结果整合到圣路易斯华盛顿大学现有的本科生/研究生课程中，为学生提供环境资源恢复方面的实践培训（包括实验课程）。此外，PI计划与圣路易斯当地高中合作，探索教师研究经验（RET）项目的开发和实施。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。

Anaerobic digestion (AD) is a promising and versatile environmental biotechnology platform for converting organic wastes to an energy-rich biogas for heating, electricity generation, and upgrading to produce renewable natural gas. AD has also shown great potential to convert organic wastes to volatile fatty acids (VFAs) which can serve as building blocks for the manufacturing of high-value products. During the anaerobic digestion of organic wastes, acetogenic bacteria generate VFAs that also serve as intermediate compounds for biogas production by methanogenic bacteria. Thus, the inhibition of methanogens has emerged as a promising strategy for enhancing the production of VFAs while minimizing biogas generation during the anaerobic digestion of organic wastes. The overarching goal of this project is to investigate the utilization of hydrogen peroxide generated from the bioelectrochemical (BEC) conversion of organic wastes to inhibit the growth and activity of methanogenic bacteria in anaerobic digesters. To advance this goal, the Principal Investigator proposes to explore the design, evaluation, and validation of an integrated and efficient AD-BEC-membrane separation system that could convert organic wastes to VFAs with high product yield and purity. The successful completion of this project will benefit society through the generation of fundamental knowledge to advance the sustainable conversion of organic wastes to high value products. Additional benefits to society will be achieved through outreach and educational activities including the mentoring of one graduate and two undergraduate students at Washington University in St. Louis.Anaerobic digestion (AD) has shown great potential to contribute to the decarbonization of the chemical industry via the conversion of organic wastes to high-value chemicals such as volatile fatty acids (VFAs) which can serve as building blocks for the manufacturing of industrially relevant products. However, the ability to tune and control the product spectrum of anaerobic digesters to maximize the yield and purity of VFAs remains a critical and unresolved challenge. The goal of this project is to explore an innovative approach to maximize the yield and purity of VFA production during the anaerobic digestion of organic wastes. To advance this goal, the Principal Investigator (PI) proposes to explore the utilization of in-situ generated hydrogen peroxide to inhibit the growth and activity of methanogenic bacteria which utilize VFAs as intermediate compounds to generate biogas in anaerobic digesters. The proposed inhibition of methanogenesis will be investigated within an integrated VFA production system consisting of an anaerobic digestor for product generation, a membrane separation module for product purification/concentration, and a bioelectrochemical reactor for in-situ H2O2 generation using organic wastes. The specific objectives of the research are to: (1) Advance the fundamental understanding of the mechanisms of methanogenesis inhibition by H2O2 during AD through integrated experimental and modeling studies; (2) Evaluate thermal or electrically driven membrane systems for the effective separation and purification of VFAs generated during AD; and (3) Explore the establishment of a translational scale system as a platform for performing a techno-economic assessment of the proposed integrated VFA production system. The successful completion of this research has the potential for transformative impact through the generation of new fundamental knowledge to advance the development and implementation of more efficient and cost-effective technologies to recover valuable chemicals and compounds from organic wastes. To implement the education and outreach activities of the project, the PI plans to integrate the findings from this research into existing undergraduate/graduate courses at Washington University in St. Louis to provide students with hands-on training (including lab sessions) on environmental resource recovery. In addition, the PI plans to explore the development and implementation of a Research Experience for Teachers (RET) program in collaboration with local high schools in St. Louis.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.