微藻-真菌协同处理微藻水热水相废水及其协同机制

Hydrothermal liquefaction (HTL) is a widely used process for bio-oil production from microalgae. However, wastewater produced in large amount during HTL of microalgae is impeding the industrialization of the process. Effective utilization of wastewater from HTL would contribute greatly to the development of HTL technology. Wastewater from HTL of microalgae is nutrients abundant with high levels of chemical oxygen demand (COD) and total nitrogen (TN), etc. Application of it as nutrients source for microalgae cultivation is increasingly attracting researchers’ interest. However, the growth of microalgae in AP is inhibited considerably because of the presence of toxic substances. Therefore, it cannot be utilized effectively by this path. In this proposal, co-culture of microalgae and fungi (filamentous fungi) consortium was proposed to cooperatively treat the wastewater (AP). The effective wastewater treatment would be achieved by screening effective microalgae-fungi consortium, optimization of the process designing and the environment for microorganisms’ cultivation. Meanwhile, the microalgae would be effectively harvested by the filamentous fungi. The mechanisms underlying AP treatment by microalgae-fungi consortium would be studied in depth to elucidate the coordination performance during the treatment. Finally, the biomass harvested after wastewater treatment would be characterized and its potential application as raw materials for HTL would also be studied. The implementation of this project would contribute to the microalgae-fungi wastewater treatment technology and promote the development of biofuel production from microalgae by HTL.

水热液化是当下微藻能源化产生物油所采用的主要工艺，但其加工产生的大量水热水相废水严重阻碍了该工艺的工业化，水热水相废水的高效资源化利用是推进该工艺发展的重要研究课题。水热水相废水中营养物质含量丰富（COD、TN等污染物含量高），目前主要尝试采用微藻培养对其进行资源化，由于其化学组成复杂，微藻生长受抑制作用明显，水热水相废水资源化利用率低。本项目首次提出微藻-真菌（丝状真菌）共培养、协同处理水热水相废水的技术路线，通过筛选驯化获得高性能藻菌微生物、优化藻菌工艺组合和培养条件等达到藻菌协同高效处理水热水相废水，同时真菌自絮凝生物高效采收微藻；并对藻菌协同去除污染物的机理进行深入探究，以阐明藻菌高效处理水热水相废水的协同机制；最后分析处理水热水相废水后的藻菌生物质的理化性质，评价其水热液化资源化的潜能。本项目的实施将推动藻菌废水处理技术的发展，并为微藻水热液化产能技术发展提供新的思路和理论依据。

水热液化是当下微藻能源化产生物油所采用的主要工艺，微藻水热液化产生的水热水相废水是影响水热液化工艺工业化的重要限制因子，水热水相废水的高效资源化利用势在必行。水热水相废水中营养物质（污染物）含量丰富、有毒有害物质多，对微藻生长抑制严重，本项目提出了微藻-真菌（丝状真菌）协同处理水热水相废水的技术路线，筛选驯化获得了高性能藻、菌微生物，对比研究了单独微藻或真菌、先微藻后真菌、先真菌后微藻、藻菌（真菌孢子）或藻菌（真菌球）共培养等工艺的废水处理效果，优化了藻菌废水处理工艺组合，并对废水处理条件进行优化，研发了先真菌（预处理水相废水）后微藻协同高效处理水热水相废水的处理工艺，同时实现了真菌自絮凝生物高效采收微藻。低温水热水相5%稀释液中先真菌后微藻的废水处理工艺对总氮（TN）、总磷（TP）、化学需氧量（COD）、氨氮等的去除率分别达到32.9%、95.3%、64.4%、27.0%。项目对藻菌协同去除污染物的机理进行了深入探究，研究发现水热水相中的氮、氧杂环类有机物、不饱和有机物及脂环族化合物等可能是限制微藻生长的主要抑制因子，真菌可对微藻生长抑制因子进行预处理，从而降低水热水相对微藻的毒害作用，而微藻则可利用二氧化碳，并为真菌提供氧气，实现了藻菌协同高效处理水热水相废水。项目系统分析了处理水热水相废水后的藻菌生物质的理化性质，其元素、生化组成与优质培养基所培养的生物质组成相似；开展了藻菌生物质水热液化研究，其产品的产率与性质较好，与原物料水热液化相比，产品无明显差异。项目构建形成了水热液化协同藻菌培养的半封闭产能系统，集成了水热水相循环促进产油、低温水热水相培养真菌-微藻、真菌-微藻协同去除污染物、真菌采收微藻及收获优质生物质等。本项目的实施可推动藻菌废水处理技术的发展，并为微藻水热液化产能技术发展提供了新的思路，奠定了理论基础。