Collaborative Research: A Novel Biological Valorization of Hydrothermal Liquefaction Wastewater with Marine Protist and its Granulated Phenotype

水热液化（HTL）被认为是一种很有前途的热能处理方法，可以从广泛的有机物质中生产生物燃料，包括农业废弃物、生物质、城市固体废物和藻类。美国能源部最近的一份报告指出，利用HTL技术，美国每年可以从可利用的废弃有机物质中生产多达59亿加仑的生物原油；这种生物原油可以进一步提炼成液体运输燃料，使用类似于传统石油精炼的工艺，取代目前由不可再生原料生产的燃料。然而，目前的HTL工艺产生大量含有高浓度有机化合物和营养物质的废水；废水的可持续处理是HTL扩大规模和商业化的最大瓶颈之一。本研究将通过从HTL废水中回收有机碳和营养物质，从环境和能源转换效率的角度来解决HTL的问题。这是提高净能源产量、增强HTL工艺的经济可行性和环境可持续性的关键一步。在实施该项目的过程中，研究人员将在生物燃料生产、生物技术/生物加工和环境管理方面培训下一代科学家和工程师，同时向公众宣传可持续生物燃料生产以及能源消耗对经济、环境和社会可持续性的影响。本课题研究小组最近发现，一种海洋原生生物Thraustochytrium striatum HB可以在城市固体废物HTL处理产生的废水中生存和生长，无需补充营养，同时去除约80%的总有机碳，100%的总氮和80%的磷。此外，在HTL废水中代谢有机化合物的微生物被发现能够耐受较宽的pH和盐度范围（与海水相当），同时能够在恶劣条件下形成细胞聚集体。因此，海洋原生生物有望成为HTL废水处理和增值的一类新型优质微生物。该项目的总体目标是建立一个纹状体hb促进HTL废水增殖的平台，使HTL可持续用于生物燃料生产。本研究的具体目的是：(1)阐明生物原油产量与HTL废水组成的相关性；(2)揭示纹状体HB对新的废水环境的代谢适应，以提高总能量回报和生物原油产量；(3)探究纹状体HB生物颗粒的形成机制及其对HTL废水增殖的影响，因为生物颗粒在废水增殖方面比分散细胞更有效。海洋原生生物有望成为处理其他类型高强度废水的一种新型微生物。拟议研究的跨学科性质将促进研究和教育计划的整合，以加强参与该项目的三所研究所的教育计划。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。

Hydrothermal liquefaction (HTL) has been considered as a promising thermal processing approach to biofuel production from a broad range of organic matter, including agricultural waste biomass, municipal solid waste, and algae. A recent U.S. Department of Energy report stated that as much as 5.9 billion gallons of biocrude could be produced each year in the U.S. from the available waste organic matter using HTL technology; this biocrude can be further refined to liquid transportation fuels using processes similar to conventional petroleum refining, replacing those fuels currently produced from non-renewable feedstocks. However, current HTL processes produce a large amount of wastewater containing high concentrations of organic compounds and nutrients; the sustainable disposal of this wastewater is one of the most significant bottlenecks to the scale-up and commercialization of HTL. This research will address concerns from both environmental and energy conversion efficiency perspectives of HTL by recovering organic carbon and nutrients from HTL wastewater. This is a critical step to increasing the net energy yield and enhancing the economic viability and environmental sustainability of HTL processes. In the course of carrying out this project, the researchers will train the next generation of scientists and engineers in biofuel production, biotechnology/bioprocessing, and environmental stewardship, all while educating the public about sustainable biofuel production and the impact of energy consumption on economic, environmental and societal sustainability.The research team of this proposal has recently found that a marine protist Thraustochytrium striatum HB can survive and grow in wastewater produced from HTL processing of municipal solid waste without supplemental nutrients while removing approximately 80% total organic carbon, 100% total nitrogen, and 80% phosphorus. Additionally, the microbes were found to be tolerant of wide pH and salinity ranges (comparable to sea water) in metabolizing organic compounds in HTL wastewater while being able to form cell aggregates under harsh conditions. Therefore, marine protists hold promise to be a new class of superior microorganisms for HTL wastewater treatment and valorization. The overarching goal of this project is to establish a T. striatum HB-facilitated platform for HTL wastewater valorization to enable sustainable HTL for biofuel production. The specific objectives of this research are to: (1) elucidate the correlation between biocrude yield and the HTL wastewater composition; (2) reveal the metabolic adaptation of T. striatum HB to the new wastewater environments to enhance overall energy return and biocrude yield; and (3) explore the formation mechanisms of T. striatum HB biogranules and the resulting performance impact on HTL wastewater valorization since biogranules are more efficient in wastewater valorization compared to dispersed cells. The marine protists could be a new class of promising microorganisms for valorization of other types of high-strength wastewater. The interdisciplinary nature of the proposed research will facilitate the integration of research and educational plans to enhance the education programs of three institutes involved in this project.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.