畜禽粪便堆肥中氮素转化的微生物驱动机制研究

Animal waste composting is an ecologically significant process linking animal industry with plant industry. The processes involved in nitrogen conversion play a crucial role in composting, possibly resulting in environmental pollution, greenhouse gas emission and loss of nitrogen. However, the knowledge of nitrogen conversion driven by microbes during composting is still inadequate,and the mechanism concerning nitrogen conversion during composting is still not clear, resultilng in the fact that no enssential progress has been made in the research of nitrogen conversion so far. In this research breakthrough is made in terms of the techniques for investigating nitrogen conversion during composting. Genes in charge of nitrogen conversion(amoA、nosZ、hzo,et al) are to be utilized in the PCR-DGGE and Real-time PCR analysis to investigate structure and function of the microbial community related to nitrogen conversion. Responding pattern of the micoorganisms to environmental changes during composting is to be illustrated, and inherent microbiological mechanism driving nitrogen conversion revealed. Based on these observations, model of nitrogen converstion during composting is to be estabslished. This research is of significance for establishing nitrogen cycling theory and controlling technology of nitrogen loss during composting. The work is also constructive for enriching the theoretical system of global nitrogen cycling. Furthermore, this research is going to provide microbiological evidence for answering the ecologically important question, "Are there anammox process and hetero-nitrification in composting"

畜禽粪便堆肥是连接畜牧业和种植业具有重要生态意义的过程。氮素转化是堆肥中关键的过程，亦是导致环境污染、温室气体排放和氮素资源损失的根源。然而，目前对堆肥中微生物驱动的氮素转化规律的认识十分局限，尚未弄清堆肥氮素转化的微生物驱动机制，导致堆肥氮素研究难以取得实质性进展。本项目克服了堆肥氮素转化研究中的技术瓶颈，以氮素转化主要功能基因（amoA、nosZ、hzo等）作为分子标记基因，利用PCR-DGGE、Real-time PCR等技术探索堆肥过程中氮素转化微生物群落结构及功能，阐明堆肥氮素转化微生物对主要环境因子变化的响应机制，揭示堆肥氮素转化的微生物驱动机制，建立堆肥氮素循环模型，为建立堆肥氮素循环理论和堆肥氮素流失控制技术奠定科学基础，对丰富全球氮素循环理论体系的内涵具有积极意义。同时，本研究还将就学术界关注的"厌氧氨氧化过程（anammox）"和"异养硝化过程"在堆肥中开展研究。

氮素转化是堆肥中关键的过程，也是导致环境污染、温室气体和氮素资源损失的根源。然而，目前对堆肥中氮素转化的微生物学认识十分局限，尚未形成完备的堆肥氮素循环理论，导致难以提出有效的堆肥控氮技术。本研究在建立标准化堆肥体系的基础上，研究了堆肥氮素转化动态规律，分析了堆肥过程中氮素转化微生物（普通细菌、氨化作用细菌、硝化作用细菌、反硝化作用细菌、厌氧氨氧化细菌）群落结构及演替动态规律，研究了氮素转化微生物对环境因子变化响应及氮素转化微生物驱动机制，首次发现了堆肥中新的氮素转化途径（即厌氧氨氧化途径）。研究表明，堆肥过程中硝化细菌AOB群落多样性与pH值呈现极显著的负相关关系，AOA群落多样性与总氮含量呈现极显著正相关关系，且其在堆肥氮素转化过程中扮演者重要角色，温度和铵态氮对厌氧氨氧化细菌群落结构变化的影响显著。本研究揭示了堆肥氮循环的内在生物学机制，完善了堆肥氮素循环模型，对于进一步研究堆肥氮素转化机制和丰富全球氮素循环理论体系的内涵具有积极的科学意义，同时为减少堆肥中氮素流失和温室气体排放、提高堆肥效率和品质提供必要的理论支撑。