餐厨垃圾干式厌氧发酵优势菌群健康演替调控技术基础

Due to the low ratio of the carbon content to the nitrogen content, the high speed of hydrolysis and acidification and the poor mobility in the Chinese food waste, the phenomena of ammonium suppression and acid accumulation in its dry anaerobic fermentation system appears readily, which influences the stability of the system. The fundamental reason lies in that the life activity of beneficial microorganisms being suppressed and resulting in microbial ecology imbalance. Therefore, in the project, aiming to maintain and restore the ecological balance of microbial environment in dry anaerobic fermentation system for the food waste, the dominant bacteria during various periods such as hydrolysis, acidification, hydrogen production, acetic acid production and methane production periods in the anaerobic fermentation process for food waste is analyzed with various relative modern molecular biological methods. The dynamic succession discipline of dominant bacteria in the system under under compulsion from the high salt content and high oil content is studied. It is also investigated how the high heterogeneity of Chinese food waste influences the healthy growth of the dominant bacteria in various fermentation periods. Then, the impacts from the factors including inoculum, temperature, pH value, agitation and nutrients, etc. on the microbiological environment are regulated to make the mechanism clear how to promote beneficial microorganisms to become the dominant bacteria rapidly and maintaining good growth. As results, it forms the technology basis of microbiological regulation and healthy succession of the dominant bacteria in dry anaerobic fermentation process for food waste based on micro-ecological balance maintenance and recovery, which provides the theoretical support to the development and application of the technology on Chinese food waste dry anaerobic fermentation.

由于我国餐厨垃圾碳氮比低、水解酸化快、流动性差，采用干式厌氧发酵容易出现“氨抑制”和“酸积累”等现象，严重影响系统运行稳定性，其根本原因在于有益微生物的生命活动受到抑制，导致系统微生态环境失衡。本项目以维持和修复餐厨垃圾干式厌氧发酵系统微生态平衡为目标，通过多种相互映证的现代分子生物学手段，对我国餐厨垃圾干式厌氧发酵水解酸化、产氢产乙酸和产甲烷等各阶段优势菌群进行分析，研究其在高含盐、高含油胁迫条件下的动态演替规律，以及我国餐厨垃圾高度异质性对各阶段优势菌群健康发育的影响,调控接种物、温度、pH值、搅拌和营养物等因素对发酵物料微生态的作用，探索有益菌快速成为优势菌并保持良好生长的促进机制，形成餐厨垃圾干式厌氧发酵优势菌群健康演替和微生物调控技术基础，为我国餐厨垃圾干式厌氧发酵技术发展和应用提供理论支撑。

本研究系统深入研究了物料特性对餐厨垃圾厌氧发酵产甲烷微生物菌群结构和功能的影响机制，厌氧发酵各阶段优势菌群动态演替规律，油脂和氨氮胁迫下的微生物菌系动态演替规律，基于驯化的耐高氨氮功能微生物菌系和代谢网络特征，为实际的餐厨垃圾厌氧发酵工艺改进提供了理论和实验基础。主要结论如下：.（1）湿热处理温度通过改变餐厨垃圾不同化学组分微观结构性质和可生化性对其产甲烷效能产生显著影响。<100℃的湿热处理仅造成淀粉su而显著促进碳水化合物发酵细菌的生长，使体系出现酸化而产甲烷受抑制，进一步提高至120~140℃可以促进蛋白水解和纤维素类氢键的断裂，从而显著促进Gelria、Enterococcus、MBA03目、Treponema等互营细菌生长，提高体系的产甲烷效率。.（2）餐厨垃圾中的有机质产甲烷顺序为碳水化合物（~12h）、蛋白质（1~3d）、纤维素和脂类（5~18d）。Syntrophobacter和Treponema降解碳水化合物，Bacteroides和Proteiniphilum为蛋白质发酵菌，Lachnospiraceae NK3A20 group、D8A目、Candidatus Caldatribacterium、Syntrophomonas涉及纤维素和脂类降解。.（3）添加Fe0-Fe2O3有助于提高Syntrophomonas丰度，促进脂类有机物转化，维持古菌的多样性和均匀度，提高物料的甲烷产率。.（4）遭遇氨氮胁迫时，与蛋白质、纤维素和碳水化合物水解有关的Proteiniphilum、Defluviitoga和Hydrogenispora可耐受较高浓度的氨氮，与长链脂肪酸β-氧化相关的Syntrophomonas和W27科几乎消失。基于驯化策略得到的微生物菌群的代谢网络较为完整，含有降解碳水化合物（Rikenellaceae RC9 gut group）、蛋白质（Proteiniphilium）、纤维素（MBA03目和Lutispora）、脂类（W5 和W27科）ih的细菌和互营菌（Treponema），提高物料甲烷产率。