微藻-酵母共培养对沼液中氮转化的协同机制

The coupling of biogas slurry treatment and bio-energy production in accord with low carbon development concept has been considered as a new way of biogas slurry treatment. Co-culture of microalgae and oleaginous yeast can strengthen the biogas slurry treatment and microbial oil accumulation comparing with mono-culture systems. Focusing on the high nitrogen characteristics of biogas slurry, the elucidation of the synergy strengthening mechanism of different nitrogen sources transformation and biological utilization in biogas slurry by microalgae and yeast is good for the establishment of control strategy and pushing the application process of co-culture system of microalgae and yeast. The project bases on the basis of previous research, under the best co-culture system, elaborate analysis of transformation and biological utilization of various forms of nitrogen in the co-culture system with a mono culture system as control. Combining with the protein Analysis of the cell extracellular enzyme which can decompose organic nitrogen and the transcriptional level analysis of key genes in the nitrogen assimilation system, to reveal the biological basis of synergy strengthening system involved in nitrogen transformation and biological utilization. Integrative consideration of microalgae, yeast cell population analysis of the co-culture system, elucidates the synergy mechanism of nitrogen transformation in the co-culture system. This study will provide a scientific basis for establishment new and efficient biogas slurry energy utilization system and low cost of microbial oil production mode.

沼液处理与生物能源生产的耦合符合低碳循环发展的理念，被认为是沼液处理的新途径。与利用沼液单独培养微藻系统相比，微藻-油脂酵母共培养可以强化沼液中营养物的去除效果及微生物油脂的积累。鉴于沼液的高氮特性，对共培养体系中微藻、酵母协同强化氮的降解、生物转化机制缺乏深入了解，不利于微藻-酵母共培养处理沼液调控策略的建立及实际应用进程的推进。本项目结合前期研究基础，在获得的最佳共培养体系中，以单培养体系为对照，精细分析培养体系中各形式氮的存在特征及变化规律，结合体系中分解有机氮的胞外酶系的蛋白组学解析、胞内氮同化关键基因的转录水平解析以及共培养体系中微藻、酵母丰度变化的细胞水平解析，揭示共培养体系协同强化氮转化及生物利用所涉及的生物学基础，阐明微藻-酵母共培养体系中氮转化的协同机制。本研究将为建立新型、高效的沼液处理耦合低成本的微生物油脂生产模式提供科学基础。

沼液处理与生物能源生产的耦合符合低碳循环发展的理念，被认为是沼液处理的新途径。微藻-油脂酵母共培养可以强化沼液中营养物的去除效果及微生物油脂的积累。鉴于沼液的高氮特性，对共培养体系中微藻、酵母协同强化氮的降解、生物转化机制的深入了解有利于微藻-酵母共培养处理沼液调控策略的建立及实际应用进程的推进。本项目通过考察甘油浓度、沼液稀释比例、微藻酵母接种比例对微藻-酵母共培养体系中氮磷等污染物去除、获得的生物质生化组成以及产出效能的影响，确立了优化的微藻-酵母共培养资源化利用沼液的培养方案；通过考察单培养和共培养体系中关键时间节点下微藻NO3-、NH4+同化关键酶基因转录水平差异，结合各体系中不同形式氮的存在特征及变化规律，解析了关键酶基因转录差异与共培养体系氮同化的协同关系；采用流式细胞术对单培养、共培养体系中的微藻和酵母细胞丰度、细胞特征进行分析，确定了培养体系中细胞丰度、大小及叶绿素含量变化规律，结合各种形式氮的存在特征及变化规律，解析了共培养体系中微藻和酵母细胞群体及个体特征的变化与氮转化同化的关系；利用新一代高通量测序技术及实时荧光定量PCR技术，解析单培养和共培养体系中关键时间节点下微藻及酵母细胞的全局基因转录水平差异，鉴别差异表达基因、获得受差异表达基因显著富集的GO terms及代谢通路、了解微藻及酵母细胞响应共培养的总体代谢调控情况，综合体系中碳、氮物质转移变化规律，阐明共培养体系中碳、氮代谢调控机制。