电极电子传递促进污泥厌氧代谢系统慢生菌功能强化研究

To promote resource recovery and energy production from waste activated sludge is one of urgent requirement for environmental safety and society development. However, microbial anaerobic conversion is a long-term process to complete degradation and biogas production, which greatly limits biological technology application to treat waste biomass. Electron transfer is the essence of anaerobic metabolism for energy recovery, and also influences microbe growth and metabolic pathway. Slow-growing bacteria (e.g.anammox, autotrophic denitrifiers, methanogens) are very important functional communities in anaerobic process to convert nutrient and biogas production. To date, slow-growing bacteria are not well understood on their growing characteristics and connections in biological process. Recently, microbial electrolysis assisted anaerobic process has been proved to be positive enhancement on complex carbon degradation and methane production rate. But the mechanism on electro-driven methane production pathway is still unclear. In this project, an integrated system of microbial electrolysis and anaerobic degradation has been built to accelerate sludge treatment and energy recovery. The connection among extracellular electron transfer bacteria and methanogens will be regulated by biocathodic reaction and electron transfer process. The electron recovery and intermediate product will be analyzed along cathode surface to suspended solution. The research on interspecies electron transfer between bioelectrode and microbial communities, especially slow-growing bacteria, will positively promote bioenergy recovery in sludge digestion process in future.

推动实现剩余污泥资源/能源回收是当前水处理发展的现实需求，但是污泥厌氧转化是一个周期较长的微生物降解过程，这限制了污泥厌氧技术应用。电子传递作为厌氧代谢产能的实质过程，同时也影响着相关功能菌的生长方式和代谢路径。慢生菌（如厌氧氨氧化菌、自养反硝化菌、产甲烷菌等）在厌氧生物处理工艺中承担着营养元素转化和产甲烷等核心作用，对系统功能稳定具有重要意义，目前对这类功能菌的调控和影响手段关注尚少。生物电解耦合传统厌氧消化对剩余污泥生物转化速率和产甲烷速率被证实具有明显促进作用，但是胞外电子传递对慢生菌主导的碳/氮转化机制尚不清晰，如何实现慢生菌功能强化和调控尚需探索。本研究在生物电极构建的厌氧强化工艺中围绕生物电极反应解析胞外电子传递菌对其他厌氧菌生长/代谢的促进作用，揭示种间电子传递或还原产物对系统中慢生功能菌的影响机制。基于电极与厌氧菌间电子传递研究将对剩余污泥厌氧产能效率提升具有积极意义。

厌氧生物碳氮转化是实现废水资源/能源回收的重要生物代谢过程，但是厌氧转化是一个相对周期较长的微生物降解过程。其中厌氧氨氧化菌、产甲烷菌等慢生菌在厌氧生物处理工艺中承担着氮素转化和甲烷回收的核心作用，目前对这类功能菌的调控和影响手段十分缺乏。电子传递作为厌氧代谢产能的实质过程，同时也影响着相关功能菌的生长方式和代谢路径，生物电解耦合传统厌氧消化对厌氧生物代谢速率和污染物降解效率具有明显促进作用，本项目在生物电极构建的厌氧强化工艺中围绕生物电极反应解析胞外电子传递菌对其他厌氧菌生长/代谢的促进作用，揭示种间电子传递或还原产物对系统中慢生功能菌的影响机制。针对碳源转化过程调控，研发了微生物电解耦合厌氧消化（ME-AD）工艺，建立了胞外电子传递提升嗜氢产甲烷菌定向富集方法，揭示了嗜氢产甲烷菌为优势菌群的高效产甲烷途径；通过计算流体力学优化配置生物电极空间分布，解析了系统内部流态和传质对电极菌群分布及功能关联规律；揭示了阴极生物膜内的质子梯度变化，证实了嗜碱产甲烷菌的优势功能地位；构建了mcrA基因对电极生物膜中产甲烷菌的绝对定量方法，揭示了电极活性微生物与产甲烷菌在内的其他功能菌的“核-壳”结构；由此提出并建立了太阳能电转化自然间歇驱动耦合工艺，发现了生物膜中与电子传递相关的细胞色素c富集及生物电子存储和释放规律，揭示了间歇式电驱动产生动态的的竞争和协作模式，使功能群落的定向选择和富集更有利于系统效能整体提升。针对厌氧氮素转化，揭示了外加电压驱动海洋厌氧氨氧化菌（MAB）生长速率的作用，施加电压降低了以单克隆抗体为基础的联合体的微生物多样性，适当的外加电压促进了EPS和血红素c的分泌，从而提高了MAB的活性，结果证明了施加外加电压是促进含盐废水脱氮和MAB活性的有效策略。研究成果在Water Research、Applied and Environmental Microbiology等环境领域专业期刊发表SCI论文20篇，其中第一标注17篇，第二标注2篇，第三标注1篇。