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

水热液化（HTL）已被认为是一种有前途的热处理方法，从广泛的有机物质，包括农业废物生物质，城市固体废物和藻类生产生物燃料。 美国能源部最近的一份报告指出，使用HTL技术，美国每年可以从可用的废弃有机物中生产多达59亿加仑的生物原油;这种生物原油可以使用类似于传统石油精炼的工艺进一步精炼为液体运输燃料，取代目前从不可再生原料生产的燃料。然而，目前HTL工艺产生大量含有高浓度有机化合物和营养物的废水;这些废水的可持续处置是HTL规模化和商业化的最重要瓶颈之一。本研究将解决从HTL的环境和能源转换效率的角度来看，回收HTL废水中的有机碳和营养物质的关注。这是提高HTL工艺的净能量产量和增强其经济可行性和环境可持续性的关键步骤。在实施该项目的过程中，研究人员将培训下一代生物燃料生产，生物技术/生物加工和环境管理方面的科学家和工程师，同时教育公众可持续生物燃料生产和能源消耗对经济的影响，环境和社会的可持续性。该提案的研究小组最近发现，海洋原生生物Thraustochytrium striatum HB可以在HTL处理城市固体废物产生的废水中存活和生长，而不需要补充营养物，同时去除约80%的总有机碳、100%的总氮和80%的磷。此外，发现微生物在代谢HTL废水中的有机化合物时耐受宽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废水处理和增殖的一类新的上级微生物。该项目的总体目标是建立一个T。纹状体HB促进HTL废水价值评估的平台，使可持续的HTL用于生物燃料生产。本研究的具体目标是：（1）阐明生物原油产量与HTL废水组成之间的相关性;（2）揭示T.纹状体HB到新的污水环境中，以提高整体能量回报和生物原油产量;（3）探讨T。纹状体HB微颗粒和由此产生的性能对HTL废水稳定化的影响，因为微颗粒与分散的细胞相比在废水稳定化中更有效。海洋原生生物可能是一类新的有前途的微生物，用于其他类型的高浓度废水的稳定化。建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个机构的教育计划。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

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.