固体有机废弃物生物堆肥碳代谢调控机制研究

In general, there are two metabolic pathways occurred in solid waste composting. One is mineralization process, in which organic matter is completely degraded to CO2, H2O and mineral. The other named biotransformation process, some intermediates in composting metabolism were recombined to more stable substances (humic substances). On the basis of previous studies, the improvement of composting efficiency resulted in large releases of CO2 was mainly concerned by many researches, while there were few consideration of the improvement of carbon biotransformation by reduction of CO2 release. Therefore, the aim of this study was to conducted to regulate tricarboxylic acid cycle (TCA cycle), the main pathways of CO2 emission during composting, to achieve the above mentioned. Firstly, the key inhibitors of TCA cycle would be optimized based on the relationship between the amounts inhibitors and the CO2 emission. Secondly, the effect of inhibitors on TCA cycle efficiency would be demonstrate by high-throughput sequencing, meta-proteomic and key functional gene analysis. Thirdly, the key micro-environment factors would be optimized among oxygen concentration, porosity, temperature, humidity. And the effect of key factors influencing on TCA cycle efficiency would be also demonstrated.Based on the above mentioned, the interaction between the intermediates of TCA cycle and the formation of humic acid would be discussed. Finally, the findings of this item can build a technic system to decrease CO2 generation, and increase the bio-fixation of carbon during composting.

生物堆肥存在有机物彻底降解（CO2、水及矿物质）、碳重新固定（形成稳定的腐殖酸类物质）两条途径。针对生物堆肥研究重视有机物快速降解途径，而对堆肥过程中碳转化固定等调控机制研究不足等问题，课题拟采用堆肥过程调控技术手段，以堆肥过程CO2减排、生物转化固碳效率提升为主要目标。选取堆肥CO2释放的重要途径三羧酸循环为主要研究对象，优选三羧酸循环关键控制因子。采用核心微生物高通量测试、元蛋白质组学特性分析、核心微生物关键功能基因分析等技术手段，阐明其对三羧酸循环效率的影响机制，揭示关键限制因子与CO2释放浓度的响应关系。通过堆肥微环境因子识别，探讨物料氧浓度、空隙率等对三羧酸循环速率的影响，优选最适微环境控制因子，揭示其影响机制。在上述研究基础上，探讨堆肥三羧酸中间产物与腐殖酸形成的互动关系，最终从堆肥生物化学、微环境及生物转化等角度，构建生物堆肥CO2减排与生物转化固碳提升相结合的技术体系。

生物堆肥有机物的转化主要存在两个途径。一方面彻底氧化分解，生成 CO2、水及矿物质。另一方面，碳素重新固定，形成稳定的腐殖酸类物质。堆肥过程中产生的CO2等温室气体，会对全球气候变暖起到加速作用，这对生态平衡及人类健康造将成巨大危害。此外温室气体的排放的同时也会带走大量的碳素和氮素，降低堆肥中腐殖酸类物质的产量和质量。因此，如何在不影响堆肥正常进行的条件下，减少堆肥中CO2排放，实现碳素可持续利用，不仅可以节能减排、降低温室效应，还能促进堆肥腐殖酸类物质的形成，具有重要的实际意义。.针对生物堆肥研究重视有机物快速降解途径，而对堆肥过程中碳转化固定等调控机制研究不足等问题，本试验选取不同农业资源废弃物，采用堆肥过程调控技术手段，以堆肥过程 CO2减排、生物转化固碳效率提升为主要目标。选取堆肥CO2释放的重要途径三羧酸循环为主要研究对象，优选三羧酸循环关键控制因子。采用DGGE、高通量测序等手段测定三羧酸调节剂对堆肥过程中微生物影响。同时结合堆肥过程中有机组分转化及腐殖酸变化规律，阐明其对三羧酸循环效率及堆肥腐殖化进程的影响机制，揭示关键限制因子与CO2释放浓度的响应关系。进一步结合堆肥关键酶活性、腐殖酸前体，如糖及氨基酸等有机组分动态变化，探讨三羧酸循环调节剂种类与浓度对三羧酸循环速率的影响。最终结果表明，对不同物料堆肥，其三羧酸循环代谢调节剂的作用存在差异。其中ATP对于提升腐殖酸效果更显著，丙二酸作为专性抑制剂对减少CO2释放效果更显著。通过对三羧酸循环的调控，初步探究了不同物料中有机组分的转化规律，同时确立了基于三羧酸循环的碳代谢调控的方法。最终从堆肥生物化学、及生物转化等角度，构建生物堆肥CO2减排与生物转化固碳提升相结合的方法。