CAREER: Expanding and controlling the product spectrum from anaerobic bioprocessing of wastes

环境工程师越来越多地利用微生物为基础的工艺从有机废物中回收有价值的资源。例如，厌氧消化被用于产生用于供暖、发电和产生甲烷的沼气。厌氧消化与链延伸已经成为一个有前途的环境生物技术平台，将有机废物转化为高价值的化学品，可以作为制造聚合物和工业相关产品的化学基石。在链延伸过程中，微生物将有机底物厌氧消化产生的挥发性脂肪酸与乙醇或醋酸盐等电子供体结合，产生更长的链化学物质。然而，调节和控制链延长微生物组的产物谱的能力仍然难以捉摸。这个CAREER项目的总体目标是推进对这些微生物组的基本理解，最终目标是开发新的和最佳的原料和反应器，以调整和控制其产品分布。该项目的成功完成将通过产生新的基础知识来促进以有机废物为原料的循环生物经济的发展，从而造福社会。进一步的社会效益将通过学生教育和培训来实现，包括在佛蒙特大学指导一名研究生和一名本科生。有机废物，如食物和农业残留物，可以转化为高价值的化学品，如中链羧酸（MCCAs），利用厌氧消化与链延长微生物群。然而，在链延长微生物组产生MCCA的基本理解方面存在关键的知识空白。首先，富含蛋白质的原料用于MCCA生产的潜力还没有得到很好的了解。其次，控制和调节通过链延伸驱动MCAAs产生的反向β -氧化途径的能力仍然难以捉摸。第三，从复杂的有机原料中模拟MCCA生产的工具才刚刚开始出现。本职业建议将解决这些关键的知识差距。提出的研究的指导假设是，厌氧微生物群可以被控制和引导，以一种可预测的方式使用氨基酸和蛋白质原料产生mcca。该研究的具体目标是：(1)评估富含氨基酸和蛋白质的底物和新的饲养策略，以定制和控制MCCA的生产；(2)设计和评估新的生物反应器，以改善MCCA的生产和提取；(3)开发计算工具来模拟链延伸生物过程。该项目的成功完成有可能产生变革性影响，产生新的基础知识，推动开发更有效和更具成本效益的生物工艺，从有机废物中回收有价值的化学品，同时减少其对环境的影响。为了实现这个职业项目的教育和培训目标，首席研究员（PI）将与佛蒙特大学（UVM） Extension 4-H合作，教授和激励高中生探索利用微生物群来保护环境和公众健康。此外，PI计划在UVM开发和教授两门新课程，包括以课程为基础的本科生研究经验，重点关注循环生物经济（生物精炼），以及一门研究生课程，帮助环境工程专业的学生使用“组学”技术和计算工具来表征和模拟与环境相关的微生物组。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。

Microbiome-based processes are increasingly being utilized by environmental engineers to recover valuable resources from organic wastes. For example, anerobic digestion is used to generate biogas for heating, electricity generation, and to produce methane. Anaerobic digestion with chain elongation has emerged as a promising environmental biotechnology platform for converting organic wastes to high-value chemicals that can serve as chemical building blocks for the manufacturing of polymers and industrially relevant products. During chain elongation, microorganisms combine volatile fatty acids generated from the anaerobic digestion of organic substrates with electron donors such as ethanol or acetate to produce longer chain chemicals. However, the ability to tune and control the product spectrum of chain-elongating microbiomes has remained elusive. The overarching goal of this CAREER project is to advance the fundamental understanding of these microbiomes with the ultimate goals of developing new and optimal feedstocks and reactors to tune and control their product distributions. The successful completion of this project will benefit society through the generation of new fundamental knowledge to advance the development of a circular bioeconomy using organic wastes as feedstocks. Further benefits to society will be achieved through student education and training including the mentoring of a graduate student and an undergraduate student at the University of Vermont.Organic wastes such as food and agricultural residues can be converted into high value chemicals such as medium-chain carboxylic acids (MCCAs) using anaerobic digestion with chain elongating microbiomes. However, there are critical knowledge gaps in the fundamental understanding of MCCA generation by chain elongating microbiomes. First, the potential of protein-rich feedstocks for MCCA production is not well understood. Second, the ability to control and tune reverse beta-oxidation pathways that drive the production of MCAAs by chain elongation has remained elusive. Third, tools for modeling MCCA production from complex organic feedstocks are only beginning to emerge. This CAREER proposal will address these critical knowledge gaps. The guiding hypothesis of the proposed research is that anaerobic microbiomes can be controlled and steered to generate MCCAs in a predictable way using amino acid and protein feedstocks. The specific objectives of the proposed research are to: (1) Evaluate amino acid and protein rich substrates and new feeding strategies to tailor and control MCCA production, (2) Design and evaluate new bioreactors for improved MCCA production and extraction, and (3) Develop computational tools to model chain elongation bioprocesses. The successful completion of this project has the potential for transformative impact through the generation of new fundamental knowledge to advance the development of more efficient and cost-effective bioprocesses to recover valuable chemicals from organic wastes while reducing their environmental impact. To implement the educational and training goals of this CAREER project, the Principal Investigator (PI) will work with the University of Vermont (UVM) Extension 4-H to teach and inspire high school students to explore the use of microbiomes to protect the environment and public health. In addition, the PI plans to develop and teach two new courses at UVM including a course-based undergraduate research experience that focuses on the circular bioeconomy (biorefining) and a graduate course to prepare environmental engineering students to use ‘omic’ technologies and computational tools to characterize and simulate microbiomes of environmental relevance.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.