基于产甲酸产乙酸菌介导种间甲酸转移的厌氧新工艺与微生物学机制

In anaerobic system, the limitation of more than two carbon VFAs syntrophic degradation and acetate utilization would result in acid accumulation. Conquering to this problem depends on the balance between this two metabolic processes and the microbial metabolic capacities strengthen of relevant functional microorganisms. The syntrophic metabolism of more than two carbon VFAs requires involvement of syntrophic fatty acid bacteria, and the process is significantly limited by the efficiency of interspecies electron transfer. This project proved that interspecies formate transfer by Formate-Producing Acetogens (FPAs) is a key step for VFAs degradation from the aspect of microbiologic, thermodynamic, molecular diffusion kinetics and the previous research work, in addition, strengthening the interspecies formate transfer will solve the problem of acid accumulation in anaerobic system and increase the anaerobic treatment efficiency at the present level. Based on this knowledge, the project proposes to strengthen the FPAs ecological function directly and indirectly to enhance interspecies formate transfer, and further to construct a new cascade degradation of organic matter by anaerobic processes. In order to provide a theoretical basis and technical basis for promoting technological innovation of anaerobic wastewater treatment, this research will focus on the following three aspects : the study on the microbial mechanism and engineering approach of increasing the formate production during anaerobic fermentation step, the study of characteristics of interspecies formate transfer through FPAs and the engineering approach of ecological function enhancement of FPAs, and the study on anaerobic process performance and microbial functional diversity of interspecies formate transfer through FPAs.

酸累积瓶颈的攻克是开发高效厌氧技术的突破口。二碳以上VFA转化及乙酸利用过程受抑制都会引起酸累积。二碳以上VFA转化需借助互营菌代谢完成，种间电子转移效率对该过程限制显著。生物学、热力学、扩散动力学及前期工作的诸多证据及甲酸扩散通量是氢气100倍的事实均证明产甲酸产乙酸菌（FPA）介导的种间甲酸转移是二碳以上VFA降解的重要环节。基于以上认识，项目提出通过提高种间甲酸转移效率并利用FPA与甲烷菌相互促进的特征使二碳以上VFA和乙酸同步高效降解的学术思路。该思路综合考虑了引起酸化问题的两个关键过程，通过强化FPA生态功能把这两个过程结合起来同时解决可从根源上攻克酸化难题。拟开展产酸发酵阶段提高甲酸产量的微生物学机制和工程学方法、种间甲酸电子传递特征与效率提高工程学方法及FPA介导种间甲酸转移的工艺性能与微生态功能多样性等三方面内容来实现研究目标，以期为推动厌氧技术革新提供理论依据和技术基础。

二碳以上VFAs的积累是厌氧消化系统效能提升的主要瓶颈，如何在保证污染物降解效果的前提下提升厌氧消化系统的工艺稳定性是目前该技术的主要研究热点。互营脂肪酸氧化菌（SFOB）与产甲烷菌的互营协作过程可以突破互营脂肪酸降解的热力学壁垒，其中由产甲酸产乙酸菌介导的种间甲酸的转移是互营协作的重要过程，通过促进产甲酸产乙酸菌与产甲烷菌的互营协作能力以及强化产甲酸产乙酸菌生态功能、从根源上解决VFAs积累问题是本项目的研究目标。本研究基于课题组前期研究证实SFOB在厌氧发酵过程的重要作用，通过宏观调控手段和微生物分析技术对产酸发酵产物组成优化、SFOB生态功能的强化以及互营共生体种间电子甲酸转移的促进的工艺和机制进行了相关研究。.通过研究本项目研发获得了一套厌氧消化发酵产酸阶段最优产甲酸工艺工程学调控方法，建立了高效产甲酸相厌氧消化系统新工艺；通过定向驯化、生物强化和外源介体介导等方法，获得甲酸产乙酸介导的种间甲酸传递过程互营共生体的生态功能强化特性和甲烷生成动力学参数；借助微生物学技术手段对其微生物群落演替及功能菌群丰度变化进行分析，获得了产甲酸菌、互营氧化菌与产甲烷菌的相互作用规律以及种间电子传递促进机制等。项目在研周期内发表学术论文25篇，其中国际重要学术期刊SCI论文21篇，申请人为通讯作者的SCI论文19篇，申请人作为通讯作者发表中文核心期刊论文4篇；投递SCI论文9篇；申请国家发明专利5项，获授权发明专利5项；参加学术会议与交流10人次并均做大会报告；培养博士生2人，硕士生3人；科研骨干中有2人职称获得晋升。