餐厨垃圾厌氧消化处理主要过程的微生物群落结构分析

【背景】厌氧消化是我国餐厨垃圾处理的主要方法,微生物在其处理过程中起到关键作用,但是目前对其不同工艺单元微生物群落结构的研究较少。【目的】通过分析各工艺单元的微生物多样性与群落结构,为改进餐厨垃圾资源化处理技术、提高资源利用效率提供科学依据。【方法】采集某餐厨垃圾处理厂油水分离、厌氧发酵、沼渣脱水等3个工艺单元产生的废液样品,采用16S rRNA基因高通量测序技术,研究其菌群组成、丰度、优势菌群及其与环境因子的相关性。【结果】初始油水分离样品中的微生物群落种类相对较少,而经厌氧发酵和沼渣脱水处理后样品中的微生物群落种类较丰富。在门水平上,厚壁菌门(Firmicutes)在各单元样品中所占平均比例最高,为81.1%,其次为拟杆菌门(Bacteroidetes)和绿弯菌门(Chloroflexi),分别占15.81%和4.59%;在属水平上,相对丰度较高的菌属为乳酸菌属(Lactobacillus)、互营单胞菌属(Syntrophomonas)等。餐厨垃圾处理过程中的部分菌属可能具有资源-环境双重属性,例如在沼渣脱水单元相对丰度高达32.67%的假单胞菌属(Pseudomonas),该菌属中既存在少部分致病菌或条件致病菌,也具有生产聚羟基脂肪酸酯的功能菌。影响各组样品微生物群落组成结构最显著的因子是p H值,其次是总糖的含量。【结论】研究明确了典型餐厨垃圾厌氧消化处理工艺单元的微生物群落结构和多样性,并提出了优化处理工艺、强化资源利用效率的建议。

Microbial community structure in the main processes of anaerobic digestion of restaurant food waste

[Background] Anaerobic digestion is the main method for treating restaurant food waste in China. Microorganism plays a crucial role in the anaerobic fermentation of restaurant food waste, however, there is limited study on the microbial structure and biodiversity in this field. [Objective] This work is aiming at providing scientific evidences for improving restaurant food waste treatment technologies and bio-resource recycling efficiency, by analyzing the microbial diversity and community structure for each processing unit. [Methods] Three waste liquid samples from typical units of oil-water separation, anaerobic fermentation, and residue dewatering were collected in a typical restaurant food waste treatment plant. The high-throughput sequencing technology of 16S rRNA gene was applied to analyze the composition, abundance, dominant microorganism, and their impacting factors. [Results] The microbial communities in anaerobic fermentation and residue dewatering samples showed higher microbial diversity than those in oil-water separation samples. At the phylum level, Firmicutes accounted for the highest proportion of 81.1% in all samples, followed by Bacteroidetes and Chloroflexi, accounting for 15.81% and 4.59% respectively, and at the genus level, Lactobacillus, Syntrophomonas, etc. had higher relative abundance. Several generic microbes had both environmental and resource properties, e.g., Pseudomonas, which accounts for 32.67% relative abundance in residue dewatering process, had the function of producing polyhydroxyalkanoates (PHA) but contained few pathogenic or opportunistic pathogenic bacteria. The most significant impacting factor of microbial diversity was pH, followed by the ammonia nitrogen content. [Conclusion] Characteristics of microbial community structure and diversity in a typical restaurant food waste treatment plant were found in this work, in addition, several recommendations for optimizing the treatment process and promoting bio-resource recycling were put forward.